UK Border Agency bosses were exposed today for detaining vulnerable children in their care in "degrading and disgraceful" conditions at Heathrow Airport.
The scandal was revealed by the airport's Independent Monitoring Board which reported that youngsters of all ages were routinely locked up in small rooms with no natural light, no access to fresh air and no bedding.
Children being held at Heathrow for immigration purposes are also forced to share space with unrelated adults for hours, the board said.
An IMB spokesman said: "This continues despite the government saying that it would end the detention of children for immigration purposes."
The watchdog called for "non-custodial, child-friendly accommodation" at Heathrow as a matter of urgency.
End Child Detention Now charity co-ordinator Esme Madill said: "This highlights the continuing contempt with which the UKBA holds its responsibilities for the welfare and safety of vulnerable children.
"It also reveals that the coalition government is still refusing to fulfil its promise to end the immigration detention of children."
A Border Force spokesman insisted it had raised the issue with Heathrow Airport's operator BAA on "numerous occasions."
But a spokeswoman for BAA denied this.
"We have had many meetings with them recently and it has not been raised," she said.
Heathrow is Britain's busiest airport where around 15,000 people are detained for immigration purposes each year, according to the board's report.
Almost 3,000 people were held for over 12 hours in 2011.