An inquiry into the running of Brooke House has heard how Custody officers smuggled in drugs for detainees to sell.
The ongoing inquiry into the removal centre, near Gatwick Airport, is examining the mistreatment of detainees, as well as the attitudes of staff.
Parcels of contraband were prepared outside and brought in by officers working for G4S.
A detainee claimed his cellmate was earning up to £400 a day supplying others in the centre.