DAVID Cameron is a prime minister given to making bold promises and, on too many occasions for comfort, even bolder u-turns.

He did not quite say that the EU referendum would not be about his leadership, no ifs not buts, but that was his hope when he sought to insist that, whatever the result on June 23, he would stay on and serve out a full term ie until 2020.

The wily old political operator, Ken Clarke, has scoffed at such a suggestion, noting how the Prime Minister “wouldn’t last 30 seconds” if the voters rejected his prospectus and opted for Brexit.

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Having, apparently, penned a resignation note should Scotland have said Yes to independence, one can only believe that on the warm morning of June 24 if the vote goes against him, a dour-faced Mr Cameron will be standing in Downing Street announcing his intention to step down in the face of his biggest humiliation.

Mr Clarke was intent on a spot of Brexit-bashing when he described Vote Leave as having become a “leadership bid for Boris Johnson”. Not content with that , he likened his Tory colleague to The Donald; albeit it, that Bozza was a “nicer version of Donald Trump”.

The attack on Mr Johnson – seen by his supporters as the true populist threat to the survival of his fellow Old Etonian – followed the barb from another Tory grandee, Lord Heseltine, who denounced the former London mayor’s rhetorical excesses as “obscene”.

The In or Out debate is fast becoming consumed by blue on blue poison and turning into something of a political soap opera.

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Europe and Britain’s relationship with it has been a seeping wound for the Conservatives, ensuring ultimate failure for the party leadership from Thatcher to Major and onto Hague; now, it is threatening Mr Cameron’s longevity.

Already three Tory backbenchers – the usual suspects of Dorries, Bridgen and Cash – have raised the prospect of a no-confidence vote in Mr Cameron; they need 50 signatures to succeed.

They would, of course, lose. But with a working majority of just 17, the PM would be hobbled in getting much legislation through if a sufficient number of Tories fail to support flagship legislation. In other words, the PM would become a lame duck premier.

The Herald:

But assuming Mr Cameron wins on June 23, there is talk of a “reunification” reshuffle or, equally, a “revenge” reshuffle; it is likely to be a bit of both.

The PM will be able to get rid of those who have misspoken themselves like Priti Patel and Penny Mordaunt, move the likes of Michael Gove and Chris Grayling to lesser jobs to ensure a suitable degree of public humiliation and lock in Boris Johnson to a difficult role, say, at the Home Office, believing that having him urinating inside the tent is far better than having him do so outside it.

Of course, if Mr Cameron were to lose on June 23, then all bets are off; the kaleidoscope would have been shaken and no one will know how the pieces will fall; not even Ken Clarke.