I want to leave American politics for a moment, although some of what is in this post can be found in the American politics of today. I leave to you to decide. And I hope you learn something.
Being somewhat of an Anglophile, I love comparative history. One can search various events in history and find commonality with the present time. I could have listed the best kings and queens, but I haven't taken the time to figure out that list; plus, one monarch may be thought of as great when they ruled, but would now be considered horrible. So it isn't an easy list to put together; conversely, the kings and queens below would be considered bad no matter when they ruled. The list is the ruling kings and queens, appended with a list of others who also badly ruled England. Enjoy.
Richard III: The worst of the the worst. While not as malevolent as the character in the Shakespeare play of the same name, King Richard III was nonetheless a bad man. Growing up during the civil war known as the War of the Roses, a 30-year battle for the throne between the royal Houses of Lancaster and York (Richard was a Yorkist), the House of York ultimately prevailed with a victory by Richard's brother King Edward IV. During this period, Richard was Duke of Gloucester who by 1483 ended up as second in line to the throne and was the most powerful noble in England. In that year, Gloucester's brother had died and the then Prince of Wales succeeded as King Edward V. Since Edward was a minor, a council was established to rule in the new king's name, a council that was set up by the king's late father before he died. However, the council did not include Gloucester. Worse, the council was determined to prevent Gloucester from pressing on with a war he was waging against Scotland. As a result, Gloucester staged a coup (within a couple of weeks after Edward's accession) and threw out the minority council and named himself as Protector (regent) of the king. Now, that wouldn't have been so bad had Gloucester stopped there. He didn't. By the end of June, 1483, before Edward was officially crowned, Gloucester had declared Edward (and the young king's brother Richard, Duke of York) illegitimate and usurped the throne, being crowned shortly thereafter as King Richard III, imprisoning Edward and Edward's brother Richard in the Tower of London. Although never definitive, it is pretty well known that Richard had his nephews killed. Having removed the previous king and marginalizing Edward's mother Queen Elizabeth (Kind Edward IV's widow), Richard's next move was to try to get rid of the only remaining threat to his throne, the Lancastrian Henry Tudor, Earl of Richmond, who had escaped to Brittany in northern France following the final victory of the Yorkist King Edward IV and had fled to France following Richard's accession. Richard's actions led to a reconciliation between the Yorkists and the Lancastrians, with Queen Elizabeth and other nobles backing Richmond after he promised to marry Richard's sister, Princess Elizabeth of York. While this was going on, Richard's son and wife died, and the king was alone. Richmond landed in England in 1485 and in August of that year, battled King Richard III at Bosworth. During the battle, Richard was killed and Richmond came to the throne as King Henry VII, marrying Elizabeth of York, and establishing the Tudor dynasty that would rule England for the next 100+ years.
Edward II: In the movie Braveheart, Edward (as Prince of Wales) was shown to be homosexual; the historical record has never proven this was or wasn't true (that movie, while well acted and a good story, is so historically inaccurate it's laughable and shouldn't be considered). Edward was the last surviving son of King Edward I ("Longshanks") and peacefully succeeded to the throne in 1307. He had had problems with his father over a knight, Piers Gaveston, who had come to England for a patronage job; Edward I had Gaveston exiled. After Edward II came to the throne, Gaveston was returned to England and given all kinds of titles and honors, with the worst being Gaveston being named Earl of Cornwall, a title usually reserved for members of the royal family. However, Edward was an incompetent ruler; fortunately for him, most of the nobles who were against the king were incompetent as well. While the nobles did manage to get rid of Gaveston in 1312, Edward was able to marginalize them for a short time. The king ruined that by trying to do battle against Robert the Bruce of Scotland (he had claimed the Scottish throne as King Robert I), losing the battle of Bannockburn in 1314. Worse, Edward neglected northern England against various attacks that came from Scotland, and had brought in new favorites, the Despensers (both father and son were named Hugh). Again, the nobles rose up, and Edward defeated them. However, another person looked to get rid of the king, Edward's wife Queen Isabella. Isabella was around 12 when she and Edward were married, and she was only a teenager when the first rebellions were going. But by 1325, she was an adult and had given birth to a son, Edward, Prince of Wales. During that time, King Edward II also had lands in France as Duke of Aquitaine, and his feudal overlord was King Charles IV of France (brother to Edward's wife Isabella). Charles had seized Edward's French lands over some dispute, and Edward had decided to send Isabella and his son to work with Charles to get the lands back and pay homage to the French king. Instead, Isabella had taken up a lover, Roger Mortimer (a noble who had been against Edward and who had escaped to France), and built up an army to overthrow her husband and place the Prince of Wales on the throne. Isabella's army landed in England in 1326, with the backing of her brother, had the Despensers killed, and captured Edward in January, 1327. She forced him to abdicate, thrown into the Tower of London, and succeeded in getting their son crowned as King Edward III, who would rule for the next 50 years. Before the year ended, the former King Edward II was dead, although from what has never been determined. (I will add further information on Isabella and Mortimer below).
Edward VIII: He is the only King of the United Kingdom on this list. From the time he was born in 1894, Edward was going to be king, being third in line to the throne following Queen Victoria. Unfortunately for Edward (along with his brother George), his parents had neglected him, leaving Edward in the care of a horrible nanny. Like other members of the royal family, Edward had military training. After the deaths of Queen Victoria (Edward's great-grandmother) and King Edward VII (Edward's grandfather), Edward's father succeeded in 1910 as King George V, with Edward being invested as the Prince of Wales. Being in the military, Edward wanted to serve at the front during World War I, but this was rejected as nobody wanted a Prince of Wales to be a casualty. Edward did serve in a limited capacity in France. But for the most part, he was groomed to become king. While very handsome and very much up on the styles of the time, Edward showed little interest in his future role, which caused much consternation for his parents. Like his grandfather, the Prince of Wales was very much a playboy, taking several mistresses and never showing any interest in getting married, that is until shortly before his father's death. Some time in the early 1930's, Edward had taken up with a Wallis Simpson, an American who had been previously divorced and who was married to someone else at the time. In January, 1936, King George V had died, and the Prince of Wales succeeded to the throne as King Edward VIII, with the coronation (official crowning) to take place a year later (a modern convention). But within a few months, Edward's mistress had decided to divorce husband and the king was bound and determined to marry her, to the consternation of the royal family, Parliament, and the British public. After months of wrangling, Edward voluntarily abdicated, the first monarch to do so, in December, 1936, a month before he was to be officially crowned. Edward's brother succeeded as King George VI, and Edward left Great Britain. Edward, given the title Duke of Windsor, married Simpson after her divorce (she was titled Duchess of Windsor), lived in France, and for a short time espoused a pro-German (pro-Nazi) position and appeasement. Some time after World War II began, he was made governor of the Bahamas, serving in that capacity for the remainder of the war. After that, he retired to France, remaining there until he died in 1972. Simpson died in 1986 and is buried next to her husband. (As a side note, Charles, the current Prince of Wales, has exhibited many of the same bad qualities as his great-uncle; it will be interesting to see what he will when and if he becomes King Charles III).
James II: He was also King James VII of Scotland (it was ruled separately from England). James, Duke of York, was the younger brother of King Charles II and son of King Charles I, who had been overthrown and executed following the English Civil War. Both Charles and York were in exile for most of the period between their father's death in 1649 and Charles' restoration in 1660. During that time, York served as a soldier in the French and Spanish armies, and had publicly converted to Catholicism during that time (his brother Charles had as well, albeit privately, keeping it quiet until a deathbed conversion in 1685). Because of this, and because Charles had no children, Parliament tried several times to keep York from succeeding to the throne, all unsuccessful. He succeeded as King James II and VII (of England and Scotland, respectively) following the death of his brother in 1685. As England and Scotland had been Protestant countries for well over 100 years, and because Catholics had been marginalized and somewhat repressed during that time, James immediately sought to rectify the situation. He espoused religious tolerance and freedom, but did so without the backing of either the English or Scottish Parliaments. Needless to say, both saw James' actions as unacceptable. Worse, James's wife Mary had given birth to a son to succeed him, James, Prince of Wales. Right away, the English Parliament, with some backing of the Scottish Parliament, worked with Mary, James' daughter from his first marriage, and her husband, the Dutch noble William of Orange, to get rid of James and put the two of them on the throne. In 1688 while James was out of London, William and Mary landed in England with an army and forcibly convinced the king to abdicate the English throne and go into permanent exile in what is known as the Glorious Revolution; in the meantime, the Scottish Parliament had deposed James as King of Scotland. After the abdication/deposition, King William III and II and Queen Mary II became joint monarchs of both England and Scotland (along with Wales and Ireland, which were a part of England at the time). Parliament then passed the English Bill of Rights in 1689 (along with Magna Carta, it was a major forerunner of the U.S. Constitution) and a first of a series of Acts of Succession which kept James' descendents from taking either the English or Scottish thrones (after the Act of Union in 1707 united England and Scotland under one government, under James' younger daughter Queen Anne, this meant James' descendents would be excluded from the throne of the United Kingdom). With the help of French troops and Irish Catholic loyalists, James went to battle against William, but was crushed. He never attempted to personally regain his throne or return to England, dying in 1701.
Charles I: Before 1612, King James I's younger son Charles was not destined to be king since he had an older brother, Henry, Prince of Wales. Nor had James given anywhere near the love and encouragement to Charles as the king had to Henry. But after Henry's death, Charles became heir to the throne, succeeding in 1625 as King Charles I of England and Scotland. His father had done much to expand the Protestantism of his predecessor, Queen Elizabeth I, building consensus by including Parliament in running the government, and keeping England out of the Thirty Years War raging on the Continent. Unfortunately, Charles was not James. Charles dismissed Parliament in 1628, not calling for another one for a dozen years. During that time, he did much to alienate the nobility and the commoners in both England and Scotland, although Charles did keep England out of the Thirty Years (he alienated the Protestant side by making peace with Catholic powers Spain and France, prior to the latter joining the Protestant side later in the war, and marrying a Catholic princess). Towards the end of his personal rule, the Scottish Parliament had rejected the Anglican Church; Charles, as Supreme Governor of that church (a title added to the ruling monarch since 1559 under Queen Elizabeth I), launched a failed military expedition against the Scots. Despite the fact that Charles had managed to raise funds without Parliament through medieval laws still in place, he had run out of money. In order to get the funds for a second expedition, Charles recalled the English Parliament to raise taxes (a requirement since 1225). Instead, Parliament, both the House of Lords and the House of Commons, began raising its own army to challenge the king, precipitating the English Civil War. Defeating Charles after a few years, he was retained as king with greatly reduced powers. But when Charles tried to regain what he saw as his divine right to rule, Parliament had Charles arrested, tried, and executed in 1649, dissolving the monarchy at the same time. Parliament, initially under Oliver Cromwell, ruled England as a Republic for the next 11 years.
Mary I: Known to history as "Bloody Mary" (an epithet sometimes wrongly attributed to Mary, Queen of Scots) and the eldest child of King Henry VIII and Queen Catherine (Catherine of Aragon, daughter of King Ferdinand of Aragon and Queen Isabella of Castile; Spain was not a unified country at the time), she was not groomed to rule England since there had never been a ruling queen before, although there was no law preventing it, and there was an excellent chance she would eventually have a brother who would succeed Henry. However, Catherine never did bear Henry a son; beginning in 1627, Henry worked very hard to annul his marriage on the grounds that Catherine had been previously married to Henry's late elder brother Arthur (who died several years before Henry became king) and the lack of a son was Henry's punishment for this "transgression". It also began about 10 years of hell for Mary as Henry turned to hating Catherine and removing Mary from the succession. Along with her mother, Mary bravely stood up to Henry as he established the Anglican religion and divorced Catherine to marry Anne Boleyn. But after Catherine died, Mary was alone. She got back into Henry's good graces and the succession following the birth of her half-brother Edward, Prince of Wales. Through the remainder of Henry's reign and all of the reign of King Edward VI, Mary maintained an outward appearance of adhering to the new religion, while inwardly maintaining her strong Catholic faith. When it was known that Edward was dying, the king had tried to exclude Mary (and her half-sister Elizabeth) from the succession by naming a cousin, Jane Dudley (Lady Jane Grey), as heir. After Edward's death, she immediately went to London to successfully claim the throne as Queen Mary I, with the backing of a majority of the nobles and the people. Immediately following her succession and coronation, Mary's policy was to restore Catholicism to the realm; many nobles fled. A few months after Mary was queen, a revolt broke out; it was crushed and led to the execution of the young Jane, imprisoned since Mary had come to London. Along with Jane, several hundred others were executed, mostly by being burned at the stake (Jane and her husband Guilford were beheaded), including the Archbishop of Canterbury Thomas Cranmer. Her half-sister Elizabeth had been brought to the Tower of London for questioning; even with the flimsy evidence needed to convict most traitors, Elizabeth was never charged with treason and was released from the Tower, although under more or less house arrest for the remainders of Mary's reign). Mary then made a very bad decision, deciding to marry her second cousin, Prince Philip of Spain, thus making him King of England; the English government managed to make sure England and Spain were to be ruled separately. For the next four years, England was fairly quiet under Mary's rule as Catholicism was expanded. However, she never produced an heir with Philip and she died in 1558. Being the first ruling queen of England was of arguable success; following the death of King Edward VI, a female was going to succeed anyway. Mary was succeeded by the second, and far more successful, female monarch, her half-sister Queen Elizabeth I.
John: John was the youngest son of King Henry II and Queen Eleanor and not expected to rule. Historians have given John a nasty reputation as a treacherous conniver, although it was fairly undeserved as he learned how to be one from his older brothers. As king, Henry was King of the English, Duke of Normandy, Duke of Aquitaine (a title he inherited when he married Eleanor), Count of Anjou, and Count of Maine; he had also been given Ireland by the Pope. He had an empire that not only included England and Ireland, but much of northern and all of western France. Henry was succeeded by his eldest surviving son King Richard I (the Lionheart), although John was in charge of Ireland, given to him by Henry a few years earlier. Richard's first order of business was to organize the 3rd Crusade; but, he first got a promise from John to stay out of England. John broke his promise not long after Richard left and made a mess of things; it didn't help that one of the crusaders, King Phillip II Augustus of France, had returned ahead of Richard and helped stir up all kinds of trouble in England and in Richard's French lands. Phillip also arranged for Richard to be kidnapped and held in custody until a ransom was paid in 1194 and Richard returned to England; despite what happened, John reconciled with Richard. Richard was married and it was expected he would have a son. By 1197, however, Richard decided to name John as his heir to all of his lands and titles, which happened two years later as Richard was fighting King Phillip of France for Richard's French lands (many of the Robin Hood stories often chastise Richard for not being a better king in England; the problem is that Richard had more land in France to deal with, and he left competent people in charge to run England in his name). Now King John, he did have a rival with a legitimate claim, Arthur, Duke of Brittany and son of John's late elder brother Geoffrey. An arrangement was worked out where Arthur would renounce his claim and John would pay homage to Phillip as the English king's overlord. John had been married to Isabel of Gloucester but had no children. John had gotten this marriage annulled and married Isabella of Angouleme, who had been betrothed to a Hugh of Lusignan. Hugh was ticked and went to Phillip, John's overlord, for restitution. Phillip demanded John report to him in France; John refused. Immediately, Phillip declared John's French lands forfeit and invested Arthur with those lands, except Normandy which Phillip kept for himself. John delayed challenging Phillip, which ended up costing John all of his French holdings except Aquitaine. Plus, John ran afoul of the Pope regarding who would be the next Archbishop of Canterbury, England's premier clerical position. John was excommunicated, which meant England was no longer under the protection of the church and no services could be done. Even after all that, John was hoarding as much money as he could, causing the currency to be horribly deflated, while at the same time, he was demanding the nobles to provide him with money in order for them to keep their lands. Even after John relented with the Church and his excommunication was lifted, things didn't get any better. In 1215, the nobles put together a document that would massively curb John's power and hold him accountable, Magna Carta. John signed off on it, but it also had to be ratified by the Pope; this was refused and civil war erupted. Additionally, Phillip decided to send his son Louis to England to help kick John out and name the French prince as the English king. John was back on offense and doing well when he died of dysentery in 1216. His 9-year old son by Queen Isabella was crowned King Henry III. Under the regency of William Marshal, Earl of Pembroke (a great warrior), the French were kicked out of England and Magna Carta was re-issued (it would be reissued two or three more times by Henry and his son King Edward I).
Henry VI: He was the only son of one of the greatest royal warriors ever known, King Henry V. By the time of the younger Henry's birth in 1421, King Henry had defeated the armies of France several times (especially in his huge victory at Agincourt in 1415) during the Hundred Years War and gotten himself named as heir to the French throne (a claim that had been made by the kings of England since 1330, and King or Queen of France of would remain part of the royal titles until 1801). However, Henry V died in 1422, and the 9-month old Prince of Wales succeeded to all of his father's titles, included as heir to the French throne, as King Henry VI. Because Henry was an infant, a regency was established, which included two of his uncles. The regency did manage England's economy pretty well; however, and within a few years, the Hundred Years War turned bad for England and Henry was never crowned King of France. Eventually, Henry had reached his majority and would rule in his own name. The bad part was that Henry was not at all like his father, being fairly uninterested in his duties as king, especially in war. He allowed favorites, especially Edmund Beaufort, Duke of Somerset, to more or less rule England. One of Somerset's enemies was Richard Plantagenet, Duke of York and heir presumptive to the throne. Somerset managed to have York sent to Ireland to govern the island. Then disaster struck in 1453; Henry had a mental breakdown that lasted for more than a year. York had returned from Ireland and was able to rule as regent in the Henry's name. Following Henry's recovery, he personally took over rule over England; however, York, who had a legitimate claim to the throne, helped precipitate the War of the Roses (Henry's Lancastrian grandfather, King Henry IV, had overthrown his cousin King Richard II in 1399 and usurped the crown over the rightful heirs, the descendents of Lionel, Duke of Clarence; York was one of those descendents). Although York was killed in battle in 1460, York's son defeated Henry the following year and was crowned King Edward IV (the same Edward who was the brother of the aforementioned King Richard III). Edward's rule was ineffective, and the man who had helped him to the throne, Richard Neville, Earl of Warwick, supported Henry's restoration despite the fact that Henry was pretty much a broken man physically and mentally. Warwick defeated Edward and Henry was back as king, but only for a short time; within a few months, King Edward IV killed Warwick and Henry's son Edward, Prince of Wales, in two different battles, and captured Henry. Without an heir, Henry was disposable, dying shortly after Edward's restoration. While Henry was an awful king, he was very pious, establishing both Eton College and King's College at Cambridge.
Stephen: Had things worked out right, King Henry I's daughter Matilda should have been the first reigning queen of England in 1135, being descended from Norman, Scottish, and English (Saxon) kings (she is known today as the Empress Matilda, having been married for a short time to a Holy Roman Emperor, and Lady of the English, having never been crowned queen). While of royal lineage, his grandfather was King William I (the Conqueror), Stephen usurped the throne from his cousin following Henry's death. He had, on at least two occasions, promised Henry to support Matilda as Queen of England, as had all other magnates in the realm. But after Henry died, Stephen claimed Henry made these promises under duress (disputed) and that Henry had named Stephen as his successor. Regardless of how he got the throne, the nobles and the Pope supported Stephen's claim and he became King of the English and Duke of Normandy (another title inherited from Henry). He did not rule well; within four years, Matilda had gathered a force to challenge Stephen for the crown. She had serious political backing; along with other disaffected nobles, her husband was one of the most powerful nobles in France, Geoffrey, Count of Anjou. By 1141, she was in London set to be crowned. But within a few months, Stephen had retaken the initiative and forced Matilda out before the coronation occurred. Her supporters continued pursuing her claim by battling Stephen, but neither she or they could never get the upper hand; worse, her husband Geoffrey never sent a major force to England to assist. However, Geoffrey did manage to kick Stephen out of Normandy and the former took over as its Duke. Geoffrey and Matilda had a son, Henry, who Geoffrey named Duke of Normandy in 1150. Henry inherited the titles and lands as Count of Anjou following his father's death a year later. Now an adult, and with the backing of his mother, Henry claimed the English throne from Stephen. Eventually, Henry and King Stephen signed a treaty where Henry would be the heir to the throne after Stephen died, even over the claims of Stephen's son Eustace, and the civil war that had been raging for about a dozen years was over. Within two years, both Eustace and Stephen's wife were dead, and Stephen was forced to accept the succession of Henry. In 1154, Stephen died of natural causes and succeeded by Matilda's son, King Henry II.
Harold (II): The Roman numerals are in parentheses because the convention of using Roman numerals following a monarch's name only began after the Normans took the throne. Harold was the second king of the Saxon kings to bear that name, the first being the Danish Harold Harefoot three decades earlier. Prior to being crowned king, Harold had been Earl of Wessex, a title he inherited from his father Godwin. For the 15 years between his father's death and the death of King Edward the Confessor, Harold was loyal, eventually becoming the most powerful man in England, after the king. Being childless, Edward's succession was not going to be straightforward. The historical record is confusing. At one point, it is said that Edward named his kinsman William, Duke of Normandy, as his heir (William was the grandnephew of Edwards mother, Queen Emma); there are also reports that Harold would support William if the Duke went to England as king. Yet, Edward found out his nephew Edward (known as Edward the Exile, son of the king's half-brother, the late king Edmund Ironside) was living in what is now Hungary and sent for him to return to England; suspiciously, Edward the Exile died within a short time after returning to England, although he had a young son, Edgar, who stayed with the king. Eventually, King Edward the Confessor died in January, 1066. It isn't clear if Edward had made a deathbed declaration that Harold should be the next king or if Harold was to rule as regent for the king's grandnephew Edgar (Edgar was still a young teenager); what is known is the Anglo-Saxon English nobles proclaimed Harold king and crowned him as such the day after Edward's death. The main problem for Harold was he wasn't of royal blood; his only connection to royalty was his one sister's marriage to Edward. Harold knew he would run into trouble with Duke William, who immediately began laying out his claim to the throne to his magnates and the Pope and preparing for an invasion; Harold gathered an army and waited near the Channel for William. What Harold didn't expect was trouble with his own family; his brother Tostig had convinced King Harold Hardrada of Norway to come, with an army, to overthrow King Harold of England. After Tostig and the Norwegian king defeated noble armies in the north, Harold took his army on a forced march to meet them. While Harold was gone, William landed in England. The English king defeated his brother and King Harold of Norway, with both being killed in battle. Then King Harold immediately marched his army south to face William. Outside of Hastings, a day-long bloody battle raged, with William defeating the Anglo-Saxon forces and seeing King Harold killed. William then marched north to London. The Saxon nobles tried to get support for Edgar to be crowned king, but were ultimately unsuccessful. On Christmas Day, 1066, with Edgar in more or less permanent exile for the rest of his life (he actually lived to be over 70 years old), the coronation of King William I took place. It could be argued that Harold wasn't really that bad a king since never really had a chance. But the historical record is not clear on whether or not he was a usurper of the throne from either Edward's grandnephew Edgar or Duke William. In any event, Harold was king for only a few months.
Here is a list of a few more people who ruled as regents in the name of the king, but not as kings or queens in their own name. The list is in historical order, not by the lack of ability, as the above list was.
Queen Isabella and Roger Mortimer (for King Edward III): After nearly 20 years of attempts to remove King Edward II, Isabella (his wife) and her lover finally did so in 1327. However, they ruled as badly as Edward; they even went so far as to recognize Robert the Bruce as King of Scots, something even Edward wouldn't do. Since King Edward III was a minor, there wasn't much he could do. Once he turned 18 in 1330, Edward decided to take matters into his own hands. Mortimer was arrested; instead of having him killed outright, Edward had Mortimer tried for treason in Parliament. After being convicted, Mortimer was hanged, drawn, and quartered, over the objections of Queen Isabella. The Queen was treated much better; Edward allowed her to retire from public life for the most part for the rest of her life (she died in 1358).
Edward Seymour, Duke of Somerset (for King Edward VI): The will of King Henry VIII called for a minority council to rule in his son's name after Henry's death. Seymour, as Earl of Hertford, was on the council; additionally, the will allowed Seymour to promote himself to be Duke of Somerset. Not long after the council began, he took over the leadership of the council and named himself Lord Protector. However, he often ruled by diktat, demanding the council to act on his orders. Somerset also kept the young king from knowing what was going on in Edward's name. But Somerset had worse problems. First, his brother Thomas was a source of consternation as he first married King Henry VIII's widow Catherine Parr while at the same time making advances towards the teenager Princess Elizabeth, the future Queen Elizabeth I. Following the death of his wife, Thomas Seymour wanted to marry Elizabeth, who would only do so if the council agreed. Instead, the council had Thomas arrested; not able to convict him of treason, he was executed after an act of attainder had been passed. Somerset's other problem was a rebellion that had broken out against his inept rule. After attempting to get the protection of the king, Somerset was arrested and thrown off the council, supplanted by John Dudley, Earl of Warwick, and soon to be Duke of Northumberland. Although restored to the council, he was arrested for trying to overthrow Northumberland and executed in 1552.
John Dudley, Duke of Northumberland (for Lady Jane Grey): Taking over from the Duke of Somerset the leadership of the minority council ruling for King Edward VI in 1551, Northumberland was an effective regent and ruled well, building consensus as much as possible, as opposed to the arbitrary rule of his predecessor; he also included the king in preparation of Edward's personal rule once he became 18. It never happened. In 1553, it was known that the young king was dying. Knowing that his Catholic half-sister Mary was next in line, Edward, with the assistance of Northumberland, changed his will. Northumberland had managed to get his son Guilford married to Lady Jane Grey, a cousin of the king and a descendent of King Henry VII; both were about 15 at the time. Edward named Jane as his successor, removing not only Mary from the succession but his other half-sister Elizabeth as well, and died on July 6, 1553. For the next nine days, Northumberland scrambled to find support for Jane and to keep Mary from the throne. He was tragically unsuccessful. Mary brought in a force to London and had Northumberland, Jane, and her husband Guilford arrested and put in the Tower. All were convicted of treason, with Northumberland being executed in August (Jane and Guilford were initially spared, but executed in 1554 after the failure of the Wyatt rebellion).
Richard Cromwell, Lord Protector of England: Richard Cromwell was the son of the previous Lord Protector, Oliver Cromwell. Oliver had initially been an MP in the House of Commons in 1628, after which King Charles I dissolved Parliament for 12 years. Cromwell was back in the Commons in 1640 when Charles recalled Parliament. He was very involved in Parliament's building up an army against Charles leading up to the English Civil War. During the war, Cromwell became one of the most powerful Parliamentarians, being one of the key people to overthrow the king and dissolving the monarchy. After a few years of not getting much done under the Commonwealth, Parliament appointed Cromwell to the position of Lord Protector; the position could be thought of as a constitutional military dictator. Although not an inherited position, Cromwell nominated his son Richard to take over after Oliver died, which occurred in 1658. Oliver Cromwell was one of England's greatest generals; Richard had no military experience whatsoever. The New Model Army had great power under the Protectorate and were not thrilled with the young Cromwell ruling over them. Factions developed which could not be controlled by the new Lord Protector. After several months, a Parliament was called and Richard Cromwell submitted a letter of resignation in 1659. Parliament restored the Commonwealth (it had been dissolved in 1653) with the goal of restoring the monarchy under King Charles II; this was completed in 1660. Cromwell went voluntarily into exile, then returned to England to live out his long life.
George, Prince of Wales (for King George III): By 1811, King George III had gone blind and became permanently insane. His eldest son George, Prince of Wales, was named regent to rule in the king's name until he succeeded to the throne. The Prince had been an embarrassment to his family, taking many mistresses and living an expensive, extravagant lifestyle. Parliament frequently appropriated thousands of pounds to make sure the Prince didn't default on his debt. As regent, the Prince took little interest in government, even as the king's armies were facing off against Napoleon, culminating in the Duke of Wellington's major victory against the French Emperor at Waterloo in 1815. In 1820, the regency was ended after the death of King George III, and the Prince succeeded as King George IV. As king, George didn't change his habits or lifestyle, ruling as king for 10 years.
There you go, the worst rulers of England and the United Kingdom for the last 1000 years.