Prison inspectors have slammed HMP Lincoln for an "unacceptable delay" in repatriating foreign nationals.
The Independent Monitoring Board for the prison says in some cases prisoners are being kept for more than a year after their sentence has expired.
It in part, it blames the loss of the dedicated foreign national liaison officer who supported those waiting deportation. Foreign nationals make up 10 per cent of the prison's population. The number rose from 42 in April 2011 to more than 100 from November 2011 to January 2012.
It also raised concerns about it taking an average 14 days to get a prisoner moved after they have been sectioned. They are held in a segregation wing which inspectors say is not fit for purpose.
A new wing is being built with completion set for September this year.