A pilot programme designed to help failed asylum seekers leave the UK voluntarily has been severely criticised by a children's charity.

A report from the Children's Society released today said the UK Border Agency (UKBA) project had shown a lack of leadership, was "flawed" in design and was not properly evaluated by the government.

Report author Lisa Nandy, the charity's policy adviser said the project had been "mismanaged from start to finish". "It wasn't clear what the UK Border Agency was trying to achieve with the project, which caused considerable confusion from the outset," she said.

Her report welcomed the government's attempt to provide a child-friendly alternative to detention for families whose asylum claims have failed, including access to local schools and accomodation in a centre that they were free to enter and leave at will.

It also questioned pilot methods such as the use of coercion - referred families could move into the centre or lose all benefits and support - and expressed "serious concerns about the way it was designed and implemented".

The 10-month long pilot was too short, her report stated, and few families were referred to the project because UKBA case managers were not aware of the scheme or were unwilling to risk missing their six-month removals target.

Management changes led to lack of leadership, she added, and contributed to a failure to evaluate the pilot systematically.

For example, the report said that data was not collected throughout the life of the pilot and the consultant employed by UKBA to conduct an evaluation was given two weeks to do so and only interviewed one family.

The report stated: "The Millbank Pilot was a missed opportunity to find out what factors help and hinder sustainable solutions for families at the end of the asylum process. The aims should have been clear at the outset and the evaluation method fully worked out."

Border and immigration minister Phil Woolas has promised that the outcome of the Millbank pilot, which saw just one family return home voluntarily, would be used to design a new pilot looking at alternatives to placing children in detention.

"The lessons we learnt have been used to design a new pilot currently running in Glasgow. This demonstrates our commitment to keep exploring alternatives to detention which increase voluntary returns and provide value for money to the taxpayer.

"This is a complex issue with no one-size-fits-all remedy, which is why these pilots are so crucial."