Kenneth Clarke has finally given up any claim on the Tory crown he sought with such determination over the last decade.

His decision not to run for a third time has all but brought an end to his frontline political career. At 63 the former chancellor now accepts he will never lead his party.

Instead he will watch from the sidelines as his long-time friend and rival Michael Howard assumes control of the Tory machine.

Contemporaries at Cambridge University in the late 1950s - and ministers in both Margaret Thatcher and John Major's governments - the two men had been written off by many.

But the sudden removal of Iain Duncan Smith left a vacancy that Howard rapidly became favourite to fill. Howard's firmly anti-euro views would have seen him triumph easily over Clarke in a poll of grassroots members.

Aware of the political realities, Clarke would only put himself forward if the rank-and-file accepted that he possessed different views on key issues.

Twice defeated, the jazz-loving MP was in no mood for a contest - seeking the leadership only if it was gifted in the manner of a coronation now afforded to Howard.

But those who write off the man in brown Hush Puppies may be forced to think again if Howard delivers victory. In the event that the new leader wins the next general election, Clarke could yet be tempted back to government in a senior role.

However for a man who has been chancellor, home secretary, education secretary and health secretary only the Foreign Office would hold some novelty value.

In the meantime, though, he has ruled out a return to the Shadow Cabinet. And despite the renewed confidence following the emergence of Howard as leader-elect, most MPs accept that the Conservatives are not destined for Number 10 at the next election.

Many will wonder how the more junior of the two colleagues managed to perform a political comeback of such proportions.

Beyond the ideological issues, Howard's decision to become shadow chancellor earned him a crucial advantage.

Unlike Clarke and big beasts such as Michael Portillo and William Hague, Howard was prepared to graft against Gordon Brown rather than accept lucrative directorships and media work.

That put him in pole position to assume the leadership and consign Clarke's career to the illustrious ranks of Conservative leaders who never were.

The Rushcliffe MP is in good company. Figures such as "RAB" Butler, Michael Heseltine and - to date - Michael Portillo all wear the badge of the nearly man.

But Clarke may look back ruefully on the three opportunities that denied him the top Tory job.

In 1997 the massacre of Conservative MPs left the party with a largely anti-European rump who preferred the inexperienced Hague to the uncompromising ex-chancellor.

Four years later a change of rules meant topping the poll of MPs - who by then were bruised by two defeats and appeared ready to agree to disagree with Clarke on Europe - was not enough to win.

Clarke took the edge over Duncan Smith and Portillo in the parliamentary ballot.

But the result was reversed among activists who could not find it in themselves to elect a pro-European to lead their depleted and demoralised party.

The scale of the pro-Howard bandwagon and the calls for unity effectively forced Clarke's hand at this, the final opportunity.

Having twice been rejected, any leadership bid would have looked like a desperate measure from yesterday's man.

A renowned cigar smoker and whisky drinker, Clarke has long been a favourite politician of voters.

But the euro-schism in the Conservative Party meant they would have rejected someone many see as their best asset for a third and final time.As Clarke said with characteristic frankness on Friday: "I'm not going to give up any other of my bad habits but coming second in Conservative leadership elections is something I don't intend to do."

"I think if I ran again, I would come second again. I can't see that would be of any use to me. It wouldn't be of any use to the Conservative Party."