Brexit victory means David Cameron's gamble has failed and he must go

The vote to leave the European Union is the biggest disruption of British politics since the 1920s, and it means the Prime Minister's career has ended in failure

Photo: Geoff Caddick/PA Wire

This is the biggest disruption of British politics since the Labour Party eclipsed the Liberals after the First World War. It is the end of David Cameron's career, which has ended as political careers so often do in failure. He gambled and lost. He is expected to address the country later this morning and, although he is likely to stay as a caretaker while a successor is elected, I expect him to announce that he will stand down later this year.

The letter from Conservative MPs urging him to stay on, even in the event of a Leave vote, is for show. The party will unite behind its leader – on condition that he is off in short order.

There are immediate practical questions. The House of Commons will meet on Monday. One of the early decisions is when to activate the two-year period for negotiating the terms of the UK's departure from the EU. That is surely a decision that Cameron has to leave to his successor, so there will be time to come to terms with the nation's decision.

That successor is almost certain to be Boris Johnson. There has been some talk in Westminster this week of Theresa May, the Home Secretary, as a "unity" candidate, but it must be remembered that the final choice of Conservative leader is made by party members as a whole. About 60 per cent of them will have voted to Leave, and they think she let them down by staying on the Remain side.

The important practical consequence of the Leave vote will be the shock to the economy. The pound has already fallen steeply overnight. The first simple implication is that foreign holidays will cost more, with a wider economic slowdown to come.

But politically the significance is that the leaderships of the four largest parties in the House of Commons has been overturned, and politics has changed utterly.

One of the people who is entitled to feel vindicated by this turn of events is Ivan Rogers, the Prime Minister’s private secretary who took the unusual step of warning him in writing against promising the referendum in 2013. I don’t know what his arguments were, but if he suggested that Cameron was unlikely to get much in his renegotiation, he would have been right. And if he suggested that such a referendum would put Britain’s EU membership at risk, he would have been right again.