The move is one of the key policies set out in the administration's first coalition pact, which will be followed by a final coalition agreement in due course.

A "significant" pupil premium for disadvantaged children and young people will also be introduced, using money from outside the existing schools budgets, funded by reductions in spending elsewhere.

On schools, the parties have agreed to allow new providers to supply state education, reform school accountability and make the National Curriculum less prescriptive.

The Child Trust Fund and tax credits for high earners will be reduced. But child poverty campaigners have welcomed the increase in the personal allowance for income tax, which should help lower and middle-income earners.

As part of a "Freedom or Great Repeal Bill" ContactPoint will be scrapped and the fingerprinting of children at school without parental permission will be outlawed.

To tackle youth unemployment, all existing welfare to work programmes will be cut and replaced with a single initiative. All Jobseeker's Allowance claimants under the age of 25 will be referred to the scheme after six months out of work.

Bob Reitemeier, chief executive of The Children's Society, and Celia Clarke, director of Bail for Immigration Detainees, have been working to end the detention of children in immigration centres as part of their OutCry! campaign. In a statement they said: "This is a major step forward for the OutCry! Campaign and we feel a tremendous reassurance that the new government is taking this so seriously. The OutCry! campaign has repeatedly condemned the unnecessary practice of immigration detention of children which seriously harms children's physical and mental health.

"We believe that locking up children, who have committed no crime, for months at a time, is unacceptable in Britain in the 21st century. This commitment is a huge step in the right direction and we now await the details of how the new administration intends to implement the policy. We urge them to end this abhorrent practice as soon as possible."  

Caroline Slocock, chief executive of RMJ, said: "We are delighted at the decision to end child detention for immigration purposes and applaud the new government for recognising the inhumanity of this practice — which treats children like criminals when they have done no crime and can leave scars for life. 

"We hope that this will be implemented immediately and that whatever measures brought in to replace detention will put the welfare and safety of these children first."

She added: "We hope that this change of policy will also extend to migrant children currently being imprisoned in this country due to disputes about their age. In all cases, children should be given the benefit of the doubt rather than running the risk of locking up children with adults.  

"We also call on the new government to review inhumane practices toward migrant children as highlighted in our report Safe at Last. The report exposed the fact that exhausted and often unwell children are being interviewed on record on arrival at Dover, without legal representation and without regard to their welfare needs."

By Lauren Higgs
Children & Young People Now-12 May 2010