Media playback is unsupported on your device Media caption Nick Clegg: warns about "siren voices on the right"

Deputy Prime Minister Nick Clegg has criticised "siren voices" among Conservatives for seeking to impose "draconian" cuts on the welfare system.

In a speech marking his five years as Lib Dem leader he claimed his party curbed plans for an extra £10bn in welfare cuts, and had "anchored reform in the sensible centre ground".

Ministers had a duty to ensure that "further reforms" were fair, he added.

But Labour accused him of trying to distance himself from broken pledges.

His speech marks the eve of the fifth anniversary of his election as Liberal Democrat leader but comes at a time when some opinion polls suggest his party has slipped to fourth, behind UKIP.

BBC political editor Nick Robinson said the deputy prime minister believed "it is time the public understood that policy-making in government is like a kitchen in which all sorts of recipes are suggested but only some make it onto the menu".

"He wants voters to know which ingredients the Lib Dems added and, just as importantly, which they insisted were left out."

'Tribal'

Mr Clegg conceded that changes to the welfare system had at times been "painful and controversial".

A new coalition split then? No, as it happens. It is often forgotten that the man who wants a Lib Dem revival almost as much as Clegg goes by the name of Cameron. Much of Labour's poll lead is rooted in defections from the Lib Dems

His party "agreed £3.8bn of benefit cuts" in negotiations on the content of the Chancellor George Osborne's Autumn Statement, he said, with benefits going up by 1% - below inflation - in line with public sector pay increases.

But, he added, the Lib Dems had blocked "more extreme" plans to "penalise families with more than two children by taking away child benefit" and "penalise young people who want to move away from home in search of a job by denying them housing benefit".

The deputy prime minister blamed the "tribal" nature of both the Conservative and Labour parties for what he sees as their inability to remain on the centre ground of British politics.

"There are some on the right who believe that no-one could possibly be out of work unless they're a scrounger," he argued.

'Total collapse'

"If you can't find a job you must be lazy. If you say you're too sick to work you're probably pretending.

"The siren voices of the Tory right who peddle this myth could have pulled a majority Conservative government in the direction of draconian welfare cuts."

By contrast, he said, the Lib Dems were "a centre-ground party" delivering "centre-ground reforms".

As ever, with the Lib Dems, they say one thing whilst doing another - resulting in a record of economic failure, trebled tuition fees, nurses cut, police axed and millions paying more while millionaires get a tax cut Harriet Harman , Labour's deputy leader

He indicated his support for means-testing of benefits such as winter fuel payments and free bus passes for pensioners, saying he would "support fairness by making clear that money should not be paid to those who do not need it - looking again at universal benefits paid to the wealthiest pensioners".

In the question session after the speech, he explained: "We have a coalition agreement commitment to maintain those universal benefits for all pensioners, so I'm not asking the prime minister to re-open that during this Parliament.

"What I'm saying... is in the future, as we make further savings... I just don't think it's justifiable or sustainable when so many other people are tightening their belts, that multi-millionaire pensioners still receive universal benefits across the board."

'Proper apology'

In his address to the Centre Forum think tank, Mr Clegg acknowledged that his party had acquired a "harder edge" since going into coalition with the Conservatives, but the alternative was "a retreat to the comfort and relative irrelevance of opposition".

He described the welfare system designed by the former Labour government as both badly designed and financially unaffordable.

"When two -hirds of people think the benefits system is too generous and discourages work then it has to be changed, or we risk a total collapse in public support for welfare existing at all," he said.

"We need welfare protection for people who fall on hard times. Of course. But you cannot ask low-income working people to pay through their taxes for people who aren't in work to live more comfortably than they do."

Labour's deputy leader Harriet Harman commented: "Nick Clegg will try every trick in the book to distance himself from the record of his government.

"But as ever, with the Lib Dems, they say one thing whilst doing another - resulting in a record of economic failure, trebled tuition fees, nurses cut, police axed and millions paying more while millionaires get a tax cut."

However, Conservative backbencher Robert Halfon agreed with the Lib Dem leader that spending on winter fuel payments and free bus passes "for pensioners in millionaire households" was "unsustainable".

"There are pensioners in my constituency on less than £10,000-a-year income and I would much rather those benefits, instead of being spread thinly to everyone, were actually focused on the poorest," he told BBC Radio 4's the World at One programme.