Lisa Nandy, The Children's Society: "The project was poorly conceived"
A £1m government scheme to help failed asylum seekers and their children return home resulted in just one family leaving Britain, the BBC has learned.
The pilot scheme in Kent, run by the charity Migrant Helpline, was aimed at reducing the number of children locked up in detention centres each year.
The Children's Society said it was a "real scandal" an opportunity to do more for the families had been missed.
The Home Office says it is committed to finding alternatives to detention.
Campaigners had estimated that each year 2,000 children are locked up in immigration removal centres with their parents who have been refused asylum.
The Home Office denies this. For the first time, it revealed to the BBC on Wednesday that 991 children were detained at Yarl's Wood immigration detention centre during 2008.
Child detention has been criticised by the Chief Inspector of Prisons, non-governmental organisations and the Children's Commissioner for England.
In an attempt to bring down those numbers, the UK Border Agency set up the one-year pilot project.
The aim was for families who had reached the end of their asylum claims to stay at an open residential unit and their children would go to school locally while ways were found to help them return home.
The project, which began in November 2007, aimed to see 260 families pass through its doors.
There was a huge amount of learning that came out of that pilot and we hope that learning will be put to good use
Roy Millard, Migrant Helpline
But the scheme, which cost just over £1m, dealt with just 13 families and only one returned home.
The first family did not arrive until the following January and the pilot ended a month early.
The Children's Society report, which evaluated the project, said referral criteria were "unclear" which resulted in unsuitable families being sent to the centre by the UK Borders Agency.
Many were referred too late in the asylum process and had laid down roots, enrolled their children in schools and had established a routine of normal life, it said.
As a result, they were allowed to return to the community.
It also said the project was not well publicised, which led to confusion at the UK Border Agency about its purpose.
Other faults highlighted in the report were a lack of clear objectives from the start and flaws in the design of the project.
The author of the report, Lisa Nandy, said: "The project was mismanaged from start to finish.
"The money would have been well spent; it's just a real scandal that the opportunity was missed," she added.
Commons Home Affairs Select Committee chairman Keith Vaz told BBC Radio 4's Today programme that referrals to the centre came too late for many families.
Most families are held at the Yarl's Wood detention centre in Bedford
"Many of these families have been sitting in the queue for years. When you deal with the case right at the end, nobody wants to go home," he said.
Roy Millard, deputy chief executive of Migrant Helpline, maintains the scheme was not a failure and said valuable lessons were learned.
"There was a huge amount of learning that came out of that pilot and we hope that learning will be put to good use," he said.
"There are complex cases, referred to in the project which we have learnt an awful lot from."
Immigration Minister Phil Woolas said: "The lessons we have learned 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."
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