The money will boost the trust fund for four-year-old Dundee twins Saul and Savannah-Rose, who suffer from infantile Battens disease, a rare genetic illness.

The disease in its later stages progresses to deterioration of the brain and nervous system, which causes blindness, seizures and severe loss of mobility and eventually death in mid childhood.

The twins are the only ones in Dundee with the illness and there are only a few cases in the UK.

The cause is being championed by fellow Castle Huntly prisoner, Michael Chaplin, who is a friend of the Fraser family.

Michael is dedicated to the cause and has enlisted a number of other inmates to be sponsored to run in the Dundee Half Marathon at the end of the month.

Castle Huntly inmates have been involved in a number of fund-raising efforts and are encouraged to choose a charitable cause as it gives them more motivation and responsibility.