The cuts, which come into effect in January, will bring in final staffing levels set for the prison after its category was downgraded from B to C.

The number of prison officers will drop from 134 to 114.

The Prison Officers' Association (POA) fears numbers may be too low but the governor has said a reorganisation of roles will make the jail more efficient.

Dartmoor is now a category C prison

Dartmoor was downgraded to category C in February.

The arbitration service, ACAS, made the decision on staffing levels to tie in with its new category.

However, the POA has said it fears it may not be enough.

Mick Chater of the POA said: "The main fears are that because of the fact that it is a bit tight, you only need to have a flu epidemic or a car accident to affect cover.

"We think it's tight, but only time will tell."

Governor Graham Johnson has welcomed the decision by ACAS and said many of the posts will be lost through natural wastage.

He said: "We'll see more efficient attendance systems for staff, so they are on duty when the work is available.

"It's about efficiency more than staff cuts."

Front-line work

Graham Johnson said many of the posts will go through a re-organisation of roles.

For instance, the man who used to meet and greet the public at the gate used to be a qualified prison officer.

He is now to be replaced by a member of the prison's support staff and put on the front-line to work with prisoners.

The changes mean there will be one prison officer for every six inmates.