New crisis for Coalition as Nick Clegg vows to block childcare reforms reforms following revolt from parent groups

Labour says apparent U-turn was 'yet another example of chaos and incompetence at the heart of government policymaking'

Plans to allow nursery staff and childminders to look after more toddlers are likely to be dropped after Nick Clegg angered the Conservatives by raising serious concerns about them.

Labour claimed the Coalition was “in chaos” after the Deputy Prime Minister threatened to pull the plug on proposals to relax childcare ratios.  He intervened after a majority of the 11,000 responses to a consultation exercise opposed the move and mothers’ groups, childcare providers and a government adviser warned it would not achieve the objectives to cut costs for parents and attract better qualified, more highly paid staff.

Furious Tories accused the Liberal Democrats of reneging on a policy due to take effect in September. The ratio for children aged under one was set to rise from three per adult to four and each adult would have been able to look after six two-year-olds instead of four as at present.  Tory ministers hope that David Cameron will overrule Mr Clegg but the policy looks doomed as it needs the support of both Coalition parties.

A Whitehall source said: “Clegg agreed this policy and has proved as trustworthy as on tuition fees and Europe referendums.”

The Lib Dems denied making a U-turn, saying they had agreed only to a consultation exercise and that it  would be foolish to plough on with a policy when there were serious doubts it would work. Mr Clegg said: “When we as a government consulted on changing the number of little toddlers that each adult can look after, the response from experts, from parents from nurseries was overwhelmingly negative. They felt that the risks outweighed the benefits and it wouldn’t necessarily reduce costs. So that’s what I still have reservations about, about this change, and that’s why we’re continuing to discuss it in government.”

Labour will stoke Coalition tensions by calling a Commons vote on the issue in the next few weeks. “David Cameron and Nick Clegg are creating chaos and confusion on childcare,” said Stephen Twigg, the shadow Education Secretary.

Elizabeth Truss, the Education Minister responsible for childcare, who was summoned to the Commons to answer an emergency question on her strategy, said England had "the tightest ratios in Europe" for children under three and the lowest staff salaries.  No one would forced to change their  ratios, she said, adding: “It is about choice.”

She admitted  the British academic establishment is  divided on the issue but insisted: “These policies are alive and well in France, in Ireland, in Holland, in Germany - there is not a single country, including Scotland, where the ratios are as low as they are here in England".

Professor Cathy Nutbrown, who reviewed childcare for the Government, welcomed Mr Clegg’s move and said children could pay "a very high price indeed" if the Government did not reconsider its plans. She told BBC Radio 4: “There’s no strong evidence that these costs really will be reduced. There’s a promise here that reducing the number of adults working with young children will reduce the cost of provision to parents and at the same time there’s a promise that staff will be better paid.”

Justine Roberts, the founder and chief executive of Mumsnet,  hoped that Mr Clegg’s intervention would result in a rethink.  She said: "Mumsnet users will be mighty relieved that some in government are listening to concerns expressed by parents and childcare professionals alike about relaxing childcare ratios. Put simply, parents believe that the quality of care will be adversely affected by the proposed changes.”