Matthew Norman: The Lib Dems may miss their chance

What a masterstroke if Clegg declared that he was ready to swap jobs with his deputy

The hour of his greatest triumph may seem an eccentric time to suggest this, but this is the perfect moment for Nick Clegg to hand Vince Cable his job. However dazzling it is, the afterglow from his Gurkhas victory should blind nobody to the fact that under him the Liberal Democrats are drifting towards another electoral disappointment.

You'd best have the smelling salts at hand for this one, but contrary to the received wisdom the only reliable guide to forthcoming elections isn't the musings of pontificating ponces like me. It's the hard cash of professional gamblers. The betting markets are uncannily accurate political predictors, and currently make the Lib Dems prohibitive odds on favourites to lose as many as a third of their 62 seats.

It is through no fault of his own that his party is poised to squander a second successive breakthrough opportunity (the last drowned in the dregs of Charlie Kennedy's Glenlivet after a woefully lacklustre campaign). A likable, intelligent and evidently sincere chap, and a gifted communicator, Mr Clegg can't help looking like the centre picture in a five part morphing sequence from Tony Blair to David Cameron.

Back in that distant era when cloning Mr Blair was all the rage, his youthful good looks made him the obvious successor to the doddery Ming Campbell, and his reassuringly middle class blandness a vital defensive bulwark against Tory resurgence in the south east.

Thirty months on, in a drastically altered world, there can scarcely be a Lib Dem member unracked by grief that the Cable guy didn't run. He declined to do so for the rationale, inarguable then, that replacing one grizzled sixtysomething baldie with another would be suicide. Who knew that his interim leadership, what with Stalin, Mr Bean and all, would prove such a startling success, and that he'd have walked it?

What we now know is that Vince Cable as leader would be a nuclear-powered magnet for disaffected and plain disgusted Labour voters sullenly shuffling towards a Conservative party whose appeal is built partly on what they are not, and partly on the pleasant inoffensiveness exemplified by Mr Clegg.

The Lib Dems lack a shred of the market distinction without which a third party is at best doomed to tread water, and to sink at worst, hence the flatlining in opinion polls at well below 20 per cent. Mr Clegg would say that this is always the case until a campaign provides intense media coverage, at which point they invariably surge, and he'd be right.

But it isn't always the case that they are gifted with a viscerally loathed, visibly disintegrating centre left government, and a PM whose demeanour in his YouTube video on expenses hints at the urgent requirement for a psychiatric conference in Vienna to consider his treatment.

They should be doing far, far better. Under Dr Cable they would be because, for all his popularity as treasury spokesman, under the presidential system into which we have drifted the identity of the party leader is paramount.

His "narrative" (dread word) is handy enough. The working class background in York is delightfully anti-Bullingdonian, and the many years of lovingly nursing his Asian-African first wife through the ravages of terminal cancer establishes him as solid and sympatique. The passion for ballroom dancing shared with his present wife leavens the possibly misleading sense of austerity (not that this isn't a colossal asset right now), and the lacerating deadpan wit is a glorious conduit to the print and TV bulletin exposure a third party craves.

Yet these are secondary factors. That everyone loves Vince Cable has become a cliche, but that they trust him is priceless. With the exception of Ken Clarke, he is the only front line politician widely believed to know what he's talking about on the economy. Few may have read his books (one, about the present crisis, newly published), but his previous career as Shell's chief economist, and his long tour de force as Cassandra warning about unsustainable personal debt, have seeped into the public consciousness. Even those who don't follow politics remember that he called it right about Northern Rock from the off.

"I told you so" is an inelegant electoral line, but a fantastically effective one. Without incessantly deploying it over Iraq, Barack Obama would still be the junior Senator from Illinois because his insurgency would never have been born. It lends an aura of sound, cool and authorative judgment worth its weight in diamond-encrusted platinum in such scary, uncertain days.

Mr Clegg may well develop gravitas one day, but as a future resident of Vienna once said, this is not the time for a novice. Today he is as secure in his post as he will ever be, while even were he weak a third Lib Dem putsch in three years is unthinkable. But he could, on the fantasy island that passes for my mind, stand aside. What a masterstroke it would be if he announced that, while he hopes to lead his party again in the future, he believes that its immediate interests, and the country's, would be best served if he swapped jobs with his deputy.

Mr Clegg would go with crowds wanting more, and be the star who won't even play that last encore. It would be an act of selfless heroism worthy of the Gurkhas themselves, and Joanna Lumley would swoon at his feet with the rest of us. He'd be transformed from promising ingenue into titan in waiting, the spread betting markets would hoik their expectations for Lib Dem seats from the low-mid 40s towards three figures, and untold phalanges of those morosely muttering about having absolutely no one to vote for – a whinge you hear incessantly these days – would feel the talons of apathy loosening their grip.

It won't happen, of course. Life and politics aren't like that, and the absurdity of heading towards a pivotal election without the country's most trusted and admired politician at the helm will sustain. And next summer, their parliamentary presence diminished by Tory raids on their marginals and having wasted their last open goal for possibly a generation, bamboozled Liberal Democrats will ask themselves what possessed them to let their party coast meekly towards the electoral rocks.