The UK Border Agency continues to detain children in "degrading and disgraceful" conditions at Heathrow Airport, a report has said.
The report by the Independent Monitoring Board (IMB) revealed that children were held in "small and stuffy" rooms. At times, they even spent the night at the non-residential facility.
Last year, 15,011 people were held in Heathrow holding rooms, with up to 3,000 being held for more than 12 hours.
The IMB said in the report that there was no natural light in some rooms where the children were held. Some had no access to open air while others had no sleeping arrangements.
"The accommodation remains unsuitable for anything but a very brief period of detention and is quite inappropriate for holding children or for overnight use,” said the report.
The children were also held with unrelated adults in rooms which only had hand basins. Terminals 3 and 4, according to the report, had the worst accommodation.
"The conditions under which children are held and that detainees have to endure overnight are degrading and disgraceful," the report said.
The report pointed out that the UK Border Agency had failed to fully carry out the improvements to the accommodation which were promised in 2011.