UK: Immigration Detention Capacity

From NCADC:

There is at present capacity for 2,644 persons in the UK Detention Estate ... Government expansion plans already agreed will increase the capacity to 2,959.

There are a considerable number of: asylum seekers/immigration defaulters held in UK prisons for indefinite periods, figures are not included in the detention estate.

There are also considerable number of asylum seekers/immigration defaulters who are held in police cells for up to seven days before being transferred to the detention estate or remanded to prison. However no figures for these people are available.

At any one time in my country, more than two and a half thousand people are imprisoned without trial and without time limit.