Failure at the top

There are some who might be tempted to feel sympathy for David Cameron for fighting to keep Britain in the EU but overwhelmed by anti-establishment nihilism and anti-immigrant fears.  No sympathy should be extended his way.  He was often described as the prep school boy who skimped on coursework but crammed for exams and came out smelling of roses.  Well, the EU referendum was one exam where he didn't have the answers and that has rebounded on the country for the worse.  Moreover, it was a completely unnecessary gamble caused by his inability to face down the EU-phobes in his party - in his weakness, he sought from the public the legitimacy he couldn't obtain through force of personality and patronage; rather the EU-phobes saw the opportunity to pull the UK out of the EU with a popular mandate to do so.  The official Remain campaign was hopelessly hamstrung Cameron and George Osborne prioritising Tory party unity ahead of winning while their opponents had no such qualms.  Winning the 2015 General Election through gobbling up the south-western seats of the erstwhile coalition partner, the Liberal Democrats, forcing Cameron to honour his referendum promise, looks ever more like a pyrrhic victory.
So, having 'lost Europe', probably losing Scotland and damaging the Northern Ireland peace process as a result and polarising the country (and let us not forget the mess in Libya), where does Cameron rank in the list of failed prime ministers.  Before the vote, people were saying if he lost he would be regarded as the worst prime minister since Anthony Eden, he of the illegal Suez debacle.  Now, with passions higher, some are speculating that history will rank him as the worst British prime minister since Lord North who ‘lost America’.
North made mistakes but the American Revolutionaries won through French and Spanish assistance and the reason Paris and Madrid could intervene was because London had previously alienated all former continental allies (hmm) who could have distracted the Bourbon monarchies by acting as Britain's sword – this was done in ministries before North and was an external factor beyond his control. By contrast, Cameron called forth his doom of his own volition, not unlike Eden, who was mentally blinkered by the 'lesson of Munich'.  Maybe Cameron could have done with that lesson on the failure of appeasing the unappeasable.
And so to the progenitors of 'Munich' - Neville Chamberlain and possibly Stanley Baldwin, both of whom may rank worse than Cameron for imperilling national security in their dealings with Nazi Germany.  Chamberlain was more culpable for British rearmament proceeded more slowly than in Germany in 'the time gained' and he also permitted the Anschluss, which undermined Czechoslovakia's defences and gave Berlin access to much needed hard currency (the Nazi economy was perpetually overheating and relied on plunder to keep going).  Baldwin has been exonerated by historians who say rearmament was not possible in the context of the contemporary public mood.  But he did sign the Anglo-German Naval Treaty, which though ultimately advantageous to the Royal Navy, unilaterally abrogated the Treaty of Versailles, enraging key liberal democracy ally France.  He also failed to forcefully intervene to prevent the remilitarisation of the Rhineland (Hitler had ordered his commanders to retreat with their tails between their legs should they encounter opposition), which set in train the following tragedies.
With North, the ‘loss of America’ was far from terminal and British trade swiftly increased after 1783. Anthony Eden and Suez, which although foolish and illegal, merely hastened the inevitable retreat from Empire. They will not be rated as bad as Cameron. Interestingly, they are Tories all.
Prime ministers, like US presidents, care about history and it will haunt Cameron to his dying day.  Unlike Chamberlain, Baldwin and Eden, he is young and will have to endure it far longer.

Top five worst prime ministers:
1. Neville Chamberlain
2. Stanley Baldwin
3. David Cameron
4. Lord North
5. Anthony Eden