Mr Clegg says the era of plenty in public spending is over
Nick Clegg is ready to ditch key Lib Dem policies in an attempt to be more honest with voters about spending cuts.
The Lib Dem leader warned party members its next manifesto could not be a "shopping list" of unfunded pledges.
He indicated that nothing was sacred - even core policies such as free tuition fees, higher state pensions and personal care for the elderly.
But Lib Dem MP Evan Harris, a member of the party's policy committee, said they would not agree to ditch such policies.
Dr Harris was adamant free tuition fees for undergraduates in particular would be in the next manifesto, as the party had only just agreed the policy and wanted to scrap Labour's 50% target for all young people going to university to help pay for it.
He said: "Nick Clegg is right to say that we will be making tough choices about what policy commitments we can afford in our manifesto given that all new spending has to be funded by cuts in other areas.
"But the media are wrong if they think that tuition fee abolition with student debt reduction will not be one of our key proposals to put before the British public."
What people want is to be treated like grown-ups
But Mr Clegg has been keen to stress that nothing is off the agenda - and that all he wants at this stage is for the party to agree a mechanism at their autumn conference in Bournemouth for deciding what should be cut.
Challenged on BBC Radio 4's PM programme about whether tuition fees would be one of the policies facing the axe, he said Dr Harris was "running ahead of the debate".
He said: "What we will be debating in the conference is not a specific list of policies. It is an approach about how we choose between different policies."
And he stressed that voters would be told before the next election which policies the party wanted to axe.
But Labour said the "u-turn" on tuition fees left the party's higher education policy "in a shambles".
"Students and the general public alike will be fed up with the Lib Dems using fees as a political football," said higher education minister David Lammy.
Mr Clegg says he wants his party to sign up to the principle that there would not be an overall increase in public spending - and that any new spending pledges would have to be paid for with cuts elsewhere.
Speaking at the launch of new policy document A Fresh Start for Britain, he said: "To my knowledge, we're the only party saying there are difficult choices. We're not going to be able to do everything we aspired to do before. We have to drop some things."
The document is short on specifics but it does identify some potential long term savings.
These include downgrading the replacement for Trident, cutting future public sector pensions, scrapping the government's "arbitrary" target of 50% of young people going to university, simplifying tax credits and cutting red tape.
It also singles out children and young people as the party's top priority and reaffirms its commitment to "clean-up" politics and bring in tax cuts for low and middle income workers paid for by green taxes on industry and higher taxes for "the rich".
Mr Clegg said more details would be revealed as the state of the public finances became clearer.
He said the party had to be "disciplined and honest" about what would be in its general election manifesto.
He said: "What people want is to be treated like grown-ups - I don't think people want a standard line from politicians that somehow the world hasn't changed - it's changed a lot. Everyone knows that.
"It seems to me that what we need to say to people is we're going to have to take difficult decisions.
"We're not going to pretend we can do everything we did in the era of plenty because it's just not plausible any more.
"But I think it's deeply unfair on the next generation to hand on to them the sins ... of this generation."
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