A young girl being held at a migrant processing centre in Kent has thrown a message in a bottle over its fence, saying pregnant women and sick people there need help.
The letter, written in broken English, said 50 families had been held at the Manston unit for more than 30 days.
It described conditions as like a prison and was addressed to “journalists, organisations, everyone”.
The Home Office said it provided for all migrants’ basic needs.
The government has faced criticism after reports that Manston was holding migrants, including families, for four weeks, in breach of the law. It is intended people stay for no more than 24 hours while their claim is processed.
At most, 1,600 migrants should be at the processing centre at any one time – council leaders in Kent said that figure was now closer to 4,000.
The letter, thrown to a PA Media agency photographer on the other side of a fence, said: “We really need your help. Please help us.”
Written on Monday it said there was a disabled child at the centre, adding “he’s really bad, they don’t even care about him”.
“It’s not easy for someone who has children … There’s a lot of children. They shouldn’t be here. They should be in a school not prison,” the letter said.
It went on to say “our food is very bad like its make us fill sick”.
The young girl was among a group of children who broke past security guards and ran over to the fence to throw the bottle to the photographer.
The letter added: “We wanna talk to you but they don’t even let us go outside.”
A Home Office spokesman said: “Manston remains resourced and equipped to process migrants securely and we will provide alternative accommodation as soon as possible.
“We urge anyone who is thinking about leaving a safe country and risking their lives at the hands of vile people smugglers to seriously reconsider.
“Despite what they have been told, they will not be allowed to start a new life here.”
The department said it provided for all the basic needs of migrants arriving in the UK, their safety and those of its staff are its utmost priority and it is committed to protecting their welfare.