The UK Border Agency (UKBA) is detaining children in "degrading and disgraceful" conditions at Heathrow airport, an official report claims today.

Children are held "almost every day and sometimes overnight" in premises that are "wholly unsuitable for the detention of children", the Independent Monitoring Board for Heathrow said.

The board said little had changed since last year despite the Border Agency's promises to the contrary – but the agency blamed the conditions on Heathrow's owner, BAA. The report said that some children are held because they are suspected to be victims of "abuse or abduction", heightening sensitivity about their treatment.

Though it praised staff, the report noted that there was no sleeping accommodation in the small rooms. It called for "non-custodial, child-friendly accommodation" to be provided "as a matter of urgency".

UKBA said: "We share the Independent Monitoring Board's concerns about the quality of the accommodation provided by BAA. We have raised this with them on numerous occasions in the past and will continue to do so."