Prospect Deputy General Secretary Leslie Manasseh said: “I welcome Nick Clegg to the growing number of people and organisations that are expressing concerns about these proposed changes.

“Prospect has consistently warned against trying to do things on the cheap, at the expense of safeguarding children. These proposals could put professionals in an impossible position and place children at risk. The Government’s advisor Professor Cathy Nutbrown has voiced her concern and now that the Deputy Prime Minister has expressed concerns too, it’s time for a swift U-turn.”

The Government’s plans will increase staff-child ratios – from 1:3 to 1:4 for one-year-olds and under in nurseries; 1:4 to 1:6 for two to three-years olds in nurseries; and from 1:8 to 1:13 for the three-plus age group in nurseries – by September this year.

The Government claims that its plans will also save money and provide better qualifications for early years professionals.

Leslie Manasseh added: “It is important to remember we already have highly trained professionals in nurseries. The Government plans to introduce EYT (early years teachers) qualifications for them. This amounts to rebadging these professionals as teachers, but without the terms and conditions that go with it. This will not help our members and will not improve the development of the children they work with.”

The Aspect Group of Prospect represents 3,000 advisory head teachers, directors and managers of children’s services, school improvement and early years advisers, education welfare officers, 14-19 coordinators, heads of Sure Start, Ofsted inspectors, parent partnership staff and self-employed consultants.