Theresa May will become the latest Tory prime minister to be brought down by the issue of Europe.
The dying days of her premiership will be dominated by the issue as she faces the same fate as David Cameron, Sir John Major and Margaret Thatcher before her.
– Margaret Thatcher
After more than 11 years in office, Mrs Thatcher was forced out of Number 10 in November 1990. Although other issues, including the hugely divisive poll tax, played a part in her downfall, ultimately it was divisions over Europe which forced her out of office.
Geoffrey Howe’s resignation speech after quitting as deputy prime minister over Europe paved the way for Mrs Thatcher’s own departure within weeks. In a scathing statement, he told MPs “the prime minister’s perceived attitude towards Europe is running increasingly serious risks for the future of our nation” and he argued that her Eurosceptic approach was damaging efforts to cooperate with the European Economic Community.
“It is rather like sending your opening batsmen to the crease only for them to find, the moment the first balls are bowled, that their bats have been broken before the game by the team captain,” he said.
– John Major
Sir John faced huge problems with the Eurosceptic wing of the Tory Party, including three Cabinet ministers he called “bastards” in comments picked up by a TV microphone.
The rows over the Maastricht Treaty were every inch as bitter as the current Tory difficulties over Brexit.
Sir John’s running battles with the Eurosceptics led him to issue a “put up or shut up” challenge, resigning as Tory leader to force a contest in 1995 in which he comfortably defeated John Redwood.
But his authority was in tatters after years of internal Conservative warfare and by the time the 1997 election came along, voters delivered a Labour landslide.
– David Cameron
The rise of Ukip and mounting pressure from Eurosceptics led Mr Cameron to promise a referendum on the UK’s membership of the EU.
The divisions in his cabinet saw senior ministers, including close friend Michael Gove, campaign for Brexit as Mr Cameron fought on the Remain side.
The historic 2016 vote saw a 52% to 48% victory for the Leave cause, which put the UK on a course out of the European Union and Mr Cameron out of office.
Just hours after the result was clear, Mr Cameron stood in Downing Street and said: “I do not think it would be right for me to try to be the captain that steers our country to its next destination.”
– Theresa May
To some extent it is a surprise she is still in Number 10, having survived a disastrous general election campaign and a botched attempt to oust her.
She has enraged Tory Eurosceptics with her Brexit deal, which they claim will keep the UK too closely aligned to Brussels.
Mrs May will have one last push to get her Brexit deal through the Commons in the week beginning June 3 and, after that, she will meet 1922 Committee chairman Sir Graham Brady to agree the timetable for her exit and the contest to replace her.
– The next Tory leader?
If Mrs May succeeds in getting her Withdrawal Agreement Bill through Parliament, then the UK will have left the European Union.
But her successor will still face lengthy negotiations with Brussels about the nature of the future UK-EU relationship, which many commentators believe will be more complicated than the divorce process.
If the Brexit deal has been rejected, whoever replaces the Prime Minister will still have the task of getting the UK out of the EU, with the same challenging parliamentary arithmetic that prevented her from succeeding.
Either way, managing a party so deeply split will provide a test every bit as difficult as that which faced Mrs May and her predecessors.