The strategy kicked off yesterday when Clegg arrived at his party’s annual conference in Bournemouth echoing Barack Obama’s mantra that he was offering "change for real". However, the atmosphere in Bournemouth presents Clegg with the same problem Tony Blair endured from 1994 till 1997: how much change will the party take before they turn against him? Blair never reached a breaking point until well into his third term in Downing Street. Clegg will enjoy no such luxury.

With activists about to be asked this week to approve abandoning their commitment to scrapping university tuition fees, alongside other severe cost-cutting measures that will hit the LibDems’ progressive credentials, there is unease in Bournemouth that has turned Clegg’s leadership speech later this week into a potential make-or-break performance.

But in a theme the grassroots will hear again and again over the next four days, Clegg offered the caveat that:"We need to treat people like grown-ups. We need to be realistic. We need to be certain we can afford it before we make promises."

Although Clegg remains a relatively unknown factor for the electorate, pollsters say that when he is given centre stage he is capable of wooing voters.

Private polling by the LibDems has told them Clegg is capable of securing the balance of power, but only if he succeeds in breaking free from his current low level of political recognition.

Party sources have admitted there is an "urgency and determination" to ensure Clegg is the "unexpected success" if Gordon Brown abandons his current "under-consideration" stance and agrees to a televised leaders’ debate during a general election campaign.

Clegg is regarded by LibDem strategists as telegenic and articulate and, when up against Brown or David Cameron, is capable of securing the vote of the undecideds.

Clegg is privately hoping a degree of realism will help boost his party’s chances at the election and is already on record as saying that anything Brown touches will "turn to dust" and that the Tories are almost certain to be in Number 10 by the summer.

The dismissal of Labour’s chances is being seen as a warning to those inside the LibDems who believe a deal should be cut on electoral reform. Clegg wants no part of any deal which has a reform vote taking place on the same day as the election, a situation he believes would set the issue back 20 years because it would be lost.

With Brown finally admitting Labour would have to cut public spending, and the Tories remaining committed to cutting spending faster than Labour, the LibDems cannot afford to be squeezed out of the spending argument due to dominate election issues.

Clegg said he is offering voters "change for real" at the election, as against a Labour government which he said had run out of road, and the Conservatives whom he branded "fake and phoney".

However, the conference in Bournemouth is not forecast to be an exercise in cheer-leading for Clegg. He has already upset the more socialist-leaning wing of party activists by claiming that "savage" cuts in spending may be needed to bring down the current £175 billion deficit.

Clegg is expected to offer more detail after hinting there should be a long-term freeze on public-sector pay, that public-sector pensions will have to be scaled back, and that the withdrawal of tax credits from the middle classes, plus an end to universal child benefit, may need to be addressed.

He said: "In some cases we will be quite bold, or even savage, on current spending, precisely to be able to retain spending where you need it."