But Lib Dem leader says it is not 'justifiable' to give handouts to millionaires

Nick Clegg predicts 2015 will be the 'first full-blown scarcity election'

The Lib Dem leader launched an extraordinary attack on the pledge made by his coalition partner that free bus passes, TV licences and winter fuel allowances would continue for all pensioners, including wealthy over-65s like Peter Stringfellow and Alan Sugar.

Mr Clegg said he would be 'gobsmacked' if Mr Cameron repeated the promise in the Tory manifesto in 2015, which he predicted would be the 'first full-blown scarcity election'.

Ahead of the last election Mr Cameron told voters they could 'read my lips' as he vowed not all pensioner benefits would continue.

But yesterday Mr Clegg said it was not fair on public sector workers or people on working age benefits who have been hit with real terms cuts to continue to fund giveaways for millionaires.

Mr Cameron is coming under growing pressure from senior ministers to drop the pledge or risk appearing to be shelter traditionally Conservative voters from cuts.

In a contemptuous swipe at the Tories, Mr Clegg said: 'When you are having to make… unprecedented savings, the idea that you exempt millionaire and multimillionaire pensioners uniquely from further savings is completely irrational.

'I would be gobsmacked in that context if any sensible, responsible political party will somehow think its explicable or justifiable that millionaire or multimillionaire pensioners are not going to be affected at all.'

Mr Clegg claimed even most wealthy pensioners did not think they should be exempt from austerity..

'You cannot ask people to take big cuts in their housing benefit, in their other benefits and say it's OK for Peter Stringfellow and Alan Sugar to be given a whole bunch of free benefits when they don't need it, paid for by other taxpayers.'

However, Mr Clegg insisted he did not back a call from former Lib Dem minister Paul Burstow that the winter fuel allowance, worth up to £300 to over-80s, be limited to just the 2million poorest pensioners.

'The question is where do you have the cut off. We haven't decided as a party,' he added.

Mr Clegg predicted that parties would offer two-tier manifesto commitments for 2015, to prepare for another coalition government. He said they would have to establish which policies they would 'die in a ditch' for, and which ones were negotiable.

Of his party's infamous U-turn on raising university tuition fees, he said: 'We're not going to make that mistake again.'

Mr Clegg said there was a 'principled case' that when doctors, teachers and nurses have had payrises capped at one per cent and benefits are capped at one per cent, it was wrong to say :

'Oh and by the way Alan Sugar you carry on - whether he receives it or not - carry on with your tax-subsidised entitlement to winter fuel payments, TV licences…