More than 100 jobs could go at Birmingham Prison as it moves from the public to private sector, its management firm has said.
Security firm G4S said around 123 full-time positions were at risk at the prison, mostly in management, operational support, facilities management and administration areas, ahead of its transfer to the private sector in October.
The new staffing levels "will be more in line with the levels G4S has successfully and safely adopted in the four other prisons it currently operates in England and Wales", a company spokeswoman said.
Jerry Petherick, managing director of G4S Offender Management, said: "Today's announcement is the culmination of several months of constructive discussions with prison staff, their representatives and the Ministry of Justice.
"Throughout this period we recognised the anxiety that many employees were feeling, and I am pleased that we have been able to stand by our earlier commitment and keep everyone informed at all stages of our consultations.
"When the Government decided to move operational control of HMP Birmingham to us, it was in the knowledge that efficiencies needed to be made. We have been transparent with staff from the very beginning, making it clear that in order to deliver the savings required by Government, some job losses were sadly inevitable.
"However, I believe for many at Birmingham, today's announcement will be welcomed - not only have we been able to minimise the number of positions at risk, and we expect this figure to fall even further - but we can now provide staff with more certainty about how they will be affected so that they are able to make decisions affecting their future."
Birmingham prison will be the first jail in the UK to be transferred from the public to the private sector.
Redundancies will be kept "to a minimum", according to G4S, and any staff affected will be able to apply for positions at the new Featherstone II prisons in Wolverhampton, which G4S will run from April next year.
Staff who join on a lower pay level than their current salary "will be entitled to a two-year financial incentive package (to be paid monthly) in recognition of the difference in terms and conditions between the private and the public sectors", a G4S spokeswoman said, adding that staff will also be able to apply to transfer to other prisons until August 26.