Conditions for women and children at an immigration removal centre are "wholly unacceptable", a report has said.
The prisons inspectorate said women at Tinsley House, near Gatwick Airport, felt intimidated and rarely left their rooms and that parents were worried about their children's safety.
In one incident at the centre, which is run by security company G4S, children were subject to "unnecessary force" while a family was being removed from the country, the report said.
Inspectors found a "prison-like culture" at the centre, which holds 120 people, mostly those awaiting deportation. Children had limited access to fresh air and the number of activities available had fallen since the last inspection, the report said.
Dame Anne Owers, the Chief Inspector of Prisons, said the report was "deeply depressing" and called for urgent action from the company and the UK Border Agency.
She said: "Provision across a number of areas at Tinsley House had deteriorated since our last visit. In particular, the arrangements for children and single women were now wholly unacceptable and required urgent action by G4S and UKBA. It is also disappointing that the opening of the neighbouring Brook House had not led to a more thoughtful and rational approach to the use of Tinsley House.
David Wood, director of criminality at UKBA, rejected the accusation that women and children faced wholly unacceptable conditions.
He said: "We accept the conditions at Tinsley House at the time of the inspection were not ideal but we do not agree that they are wholly unacceptable for women and children.
"However, we are nonetheless reviewing our services. Treating women and children with care and compassion is a priority for the UK Border Agency,
"Removal centres are a necessary part of enforcing immigration control. It is vital that they are well-run, safe and secure. Detainees are cared for with respect, with access to a range of medical, educational and welfare facilities."