Why David Cameron's job is in peril even if he wins the EU referendum

John Major has just joined David Cameron on a Remain campaign stop in Bristol.

And the former Tory Prime Minister spoke in front of the current Tory Prime Minister about the troubles he had with Europe in the 1990s.

"I remember very well," he said the arguments in those days "which wrecked many of the plans I hoped to achieve as Prime Minister."

Now, if this goes the wrong way for David Cameron tomorrow, his time in Number 10 could be rapidly over.

But if he wins - especially with a small margin - his job will still be precarious.

David Cameron has already announced he's off before 2020.

And his MPs - half of whom are campaigning on the opposite side to him in this referendum - are already looking towards his replacement.

So the story doesn't end on Friday if there is a Remain result.

It might only just be beginning.

Perhaps - on the campaign bus right now - John Major is giving David Cameron some very valuable advice.

But if Mr Cameron loses on Friday, most people think he will join John Major on the shelf of *former* Prime Ministers.