PERHAPS the greatest mystery about David Cameron is how a leader who is so popular can have so few friends?

Make no mistake, the Prime Minister remains his party’s greatest asset and his personal ratings comfortably outperform those of the Conservative Party.

Thinking Tories must consider the options should Mr Cameron fall under a bus – the harsh figure of George Osborne, the failure that was William Hague, the comedy of Boris Johnson – and break into a cold sweat.

Yet, one week after the great Euro-bust up, it is clear the Prime Minister faces extraordinary anger among his natural supporters, especially for someone who has been in Downing Street for just 18 months.

Many Tory MPs are seething over the aloofness of the Cameron inner circle and his tendency to surround himself with aides from Eton, or similarly-privileged backgrounds.

Some have never forgiven him for failing to win outright last year, despite his mission to “detoxify” his party which involved painful criticism of so much that the faithful hold dear.

Most of all, of course, they resent the compromises made over the hated European Union in order to pacify the Liberal Democrats, without whom Mr Cameron would not be in power.

Nearly half of his backbenchers defied the whip to back an EU referendum last week – and many are vowing to pursue four years of trench warfare to get their way.

Their mood wasn’t improved by an aggressive operation to try to force Tory MPs into line. One MP said: “The message was clear – don’t darken my door if you vote against me.”

Intriguingly, that treacherous atmosphere is echoed in what used to be Fleet Street, where at least three Tory newspapers are also gunning for Mr Cameron over Europe.

Key Conservative commentators have always been suspicious of the man who branded himself “heir to Blair” and who epitomised a touchy-feely Conservatism so foreign to the Blessed Margaret.

On the other side of the political divide, many who leaned towards Mr Cameron as a different type of Tory feel betrayed by a policy agenda nor far removed from Thatcherism.

There are also very few true “Cameroons” in the Cabinet. I can think only of Education Secretary Michael Gove and Culture Secretary Jeremy Hunt.

Compare all that to the way Tony Blair walked on water for so many years – with both adoring backbenchers and a largely-pliant press.

A leader can benefit enormously from floating above narrow party prejudices but, in politics, a lack of friends can be fatal.

JARROW MP Stephen Hepburn was praised for his dignified debate, this week, in salute of the famous Jarrow Crusade, on its 75th anniversary.

But the Labour MP couldn’t resist this quip: “If I had a pound from everyone I have met in the Palace of Westminster who, when I said I came from the town of Jarrow, asked ‘How did you get here? Did you walk?’, I would be a wealthy man.

“I might, perhaps, even be wealthy enough to qualify for Mr Cameron’s Cabinet.

“I should also like to clarify that there were 200 marchers. Judging by the number of people who have claimed to be a descendant of one of the marchers, anyone would think that there had been 2,000 of them.”