The prison service runs one immigration removal centre in which detainee pay is as set out in the Secretary of State for the Home Department’s previous answer. Immigration Detainees detained in a prison have the same rights as a remand prisoner. Where a detainee undertakes work in a prison he or she will be paid the rate paid to other prisoners in that prison.
This means the pay rate will vary nationally depending on the work being done by the detainee and the pay rates determined by the Governor. Governors have discretion to determine local pay rates that reflect their prisoner population needs, the type of prison, the regime in operation, and the jobs / educational / vocational training that are available.
Governors must pay at least the national minimum rate of £4 per week (Prison Service Order (PSO) 4460 sets out the national policy for Prisoners’ Pay), though in many cases the rate will be considerably higher. Prisoners or immigration detainees who want to work but for whom no suitable employment is available, or who are unable to work, receive the minimum ‘unemployment’ pay of £2.50 per week.
A copy of the PSO can be found here: https://www.justice.gov.uk/offenders/psos