Leaders in perfect position to be stabbed in the back

You'll recall that even in Act I scene 2, when he announced: "Speak; Caesar is turned to hear", Julius conspicuously failed to turn far enough to pay any attention to the advice he was offered by the soothsayer - with deleterious, knife-crime-related results.

Leaders of political parties are even more ludicrously self-important than people who buy books encouraging middle-managers to model themselves on Caligula, Carl von Clausewitz or Attila the Hun. But then so, for the most part, are their followers. Anyone prepared to stand for election is inviting people to take a stab at them: by a cheering coincidence, the Latin for "he stood" is "stabat".

The resemblances between Ed Miliband and Julius Caesar are not, perhaps, very pronounced, but Andy Burnham, a former rival for the leadership, has not let that dissuade him from auditioning for the role of Gaius Cassius Longinus. You could tell by the way he stressed that he had "the utmost respect" for his leader that he had just put down his Sabatier sharpening steel.

While Mr Burnham's declaration that his leader needs to raise his game may, as some cynics have suggested, have been pre-emptive, prompted by the fear that he is about to be demoted from his role as Shadow Health Secretary, that doesn't mean it's not true.

Labour, though still ahead in the polls across the UK, has a lead which is very slight, given the painfulness - even for those who think them necessary - of the Coalition's policies. And worryingly (from Labour's point of view), the most recent economic news has been, if not great, more encouraging.

It turns out there was no double, let alone a treble, dip recession; manufacturing, construction, retail and service sectors are at last growing, albeit not by much; the new Governor of the Bank of England has offered stability on interest rates; house prices are rising (in my view a bad thing, but never mind); and new jobs are being created, even if real earnings are still tight.

Labour's worst problem, however, is Mr Miliband himself. He is not only less popular, and regarded as less capable, than David Cameron, but less well-regarded than the party he leads - even among its own supporters.

Mr Cameron, by contrast, is much more popular than his party. That "popularity", I should stress, is relative. The Prime Minister's approval rating is currently around -15, while his party's is about -25. But then Mr Miliband's approval is around -22 and Labour only -11.

In any case, history suggests that voters are more likely to back a leader they like, even if they are suspicious of much of his or her party, than to support a party led by someone they think isn't up to the job.

The fact that neither party can yet present a political narrative which the electorate finds both attractive and credible, and which is at the same time acceptable to their own core constituencies, may be responsible for Mr Miliband's paralysis.

However, it's also the cause of Mr Cameron's contortions, as he spins around trying to keep from getting it in the back from his own supporters.

The recent emphasis on issues such as immigration - with vans emblazoned with the message Go Home or Get Arrested driving around central London - is clearly designed to reconnect with former and potential Tory voters, and backbenchers, who don't think much of the Prime Minister's previous enthusiasms, such as gay marriage, subsidies for green energy, and "hugging a hoodie".

At the weekend, the man who wrote the speech in which that last phrase appeared, Danny Kruger, expressed disappointment the Conservatives were concentrating on "skivers" and "bashing burglars and sending immigrants home", rather than "compassionate Conservatism" and the Big Society, on which Mr Cameron tried to reposition the party.

Mr Kruger - I should mention that I used to work with him, and hold him in high regard - now runs a charity for the rehabilitation of prisoners, so his comments were not back-stabbing for personal political advantage.

Even if his remarks were delivered more in sorrow than in anger, though, they won't be thought awfully helpful in Number 10.

I have some sympathy with his complaint - crime has fallen to genuinely historic lows (10% in the last year alone), and the scare-mongering about immigration is simply not borne out by the facts on its costs.

However, Mr Cameron's new stance may well be more in tune with the public mood. Even so, I doubt that it will necessarily help him.

The section of the population most receptive to the emphasis on populist issues is largely composed of people who have already decided that Mr Cameron is a dead loss. They are old-fashioned Tories and new UKIP voters who are sceptical of climate change, worried about immigration, believe (despite the evidence) that crime is rising and disapprove of same-sex marriage.

As I've pointed out before, this element of the electorate is more numerous than media coverage suggests, but not big enough to win an outright majority on its own. It may, however, be big enough to prevent the Conservatives from gaining a majority.

So the leaders of both main UK parties have the same problem about which direction to face: toward their own parties and natural supporters, or the undecided portion of the electorate? And the critics within their parties have to decide whether to raise their daggers.

Labour's leader is useless, but there is no one available as an obvious improvement - and besides, despite Mr Miliband's deficiencies, the party is still ahead.

Many Tories don't like their leader, but the public like him much more than they like them. In any case, Boris Johnson, the only obvious potential improvement in terms of bringing in the votes, is - quite apart from being a cannon so loose it may as well have swivel wheels and be packed with unreliable TNT - not even a member of parliament.

The Ides of March are some distance off, even if both leaders can hear the sabres beginning to rattle.