Media playback is unsupported on your device Media caption Nick Clegg told the BBC the Conservatives are "kidding themselves" over their spending plans

The Conservatives must "come clean" about spending plans should they win the general election, says Nick Clegg.

The Lib Dem deputy PM told the BBC his coalition partners planned to "pare back" the state "remorselessly" after 2017 and their plans did not "add up".

Earlier, Conservative Chancellor George Osborne suggested Mr Clegg's party planned "hefty income tax rises".

Labour's Chuka Umunna said spending cuts were "pulling the rug from under people".

The three largest Westminster parties have been accused of being unclear about how they would reduce borrowing by closing the gap between tax revenues and spending in the next Parliament, following the latest figures in the Autumn Statement this week.

Mr Clegg told BBC One's Andrew Marr Show: "I just think the Conservatives are kidding themselves and seeking to kid British voters if they are claiming that it's possible to balance the books, deliver unfunded tax cuts, shrink the state and support public services in the way that everybody wants. It just doesn't add up."

'Big differences'

"Under George Osborne's approach, once we balance the budget in 2017/8, they would want to pare back remorselessly, year in, year out, the state."

"I do think the Conservatives now need to come clean. Because they are not being very straightforward with people. Nick Clegg, Deputy PM

He again dismissed suggestions the reason he was not in the Commons for the Autumn Statement was because he did not want to be seen sitting next to his coalition partners, telling the programme it was "a bit too late for me to somehow avoid photo opportunities with David Cameron and George Osborne".

He said it was a "coalition Autumn Statement" - and both parties agreed on the need to tackle the structural deficit by 2017 but after that "there are some big differences" - particularly on funding public services.

Under Conservative plans the "working age poor" - people who get some benefits even if they are in work, and public services like policing, schools and social care - would be "hit very hard indeed", Mr Clegg said.

"I do think the Conservatives now need to come clean. Because they are not being very straightforward with people. How many colleges would be closed? How many primary schools would be closed? How many police would be taken off our streets?"

I think that politicians should solve the debt problems by delivering services more efficiently - not take the easy way out and dump the problem on families with hefty income tax rises. George Osborne, Chancellor

He would not confirm whether the Lib Dems would rule out removing child benefit from all but the first two children, or further cuts to the Army - both suggestions in Sunday's papers. But he said the government should "start from the top" - for example by removing free TV licences and winter fuel payments for wealthy pensioners.

He also suggested that some Conservatives privately supported his plans for a mansion tax - tied in to the council tax band system - despite the fact that they "constantly reject it in public".

The deputy prime minister was interviewed after a Sunday Times interview with Chancellor George Osborne who said that, under Lib Dem plans, income tax or National Insurance would have to rise to cut the deficit.

Tough decisions

Mr Osborne said electing either a Labour or Lib Dem government would mean a "return to economic chaos" and said the Lib Dems "shouldn't pretend to people that the sums required can be achieved by their homes tax alone".

"If you want higher taxes to do the heavy lifting, you'd also need to increase taxes like income tax or national insurance.

He added: "I think that politicians should solve the debt problems by delivering services more efficiently - not take the easy way out and dump the problem on families with hefty income tax rises."

What we have seen here is a heartless and hopeless government. Chuka Ummuna, Shadow Business Secretary

In his Autumn Statement, Mr Osborne said that although borrowing was set to be £91.3bn this year - above the forecast £87bn - the longer term outlook was rosy, with the UK "out of the red and into the black" by 2019/20. But Labour has accused him of not being straight about the figure as it had been revised up by £4.9bn this year, and by £7.6bn in 2015.

Shadow Business Secretary Chuka Umunna told the Andrew Marr Show that Labour would take "tough decisions" to bring the nation's debt and deficit down but said he could not "spell out a budget" to show where a Labour government would make cuts, when he had not seen the 2015 Budget yet.

He said Labour would focus on improving wages - citing falling income tax revenue as one of the reasons Mr Osborne had struggled to meet his targets on deficit reduction - and said Labour would cap child benefit increases at 1% in the next Parliament and would not give wealthy pensioners winter fuel allowance.

"What we have seen here is a heartless and hopeless government. Hopeless because they have fundamentally failed to meet their deficit and and debt targets and frankly heartless because they view a conception of the state that we have not seen since the 1930s, which involves pulling the rug from under people instead of empowering them to meet their dreams and aspirations."