Prison staff were not to blame for the death of an inmate, a fatal accident inquiry has found.
Kilmarnock prison had housed William McPherson for 12 months
William McPherson, 65, died in December in Kilmarnock Prison, 12 months into a five-year sentence for drug dealing.
He died in his sleep from a heart attack and lay for about 12 hours before staff noticed something wrong.
Sheriff Alistair Watson concluded that he found "no failure on the part of anyone which might in any way have contributed to his death".
Kilmarnock Sheriff Court heard McPherson had a number of ailments including diabetes and heart problems.
He was last seen alive on the evening of 6 December, 2005.
Early the following morning a prison officer looking through the cell door spy hole saw him apparently sleeping on his bed and decided not to disturb him.
He was later found to be dead.
McPherson was sentenced to 26 years in March 1972 for raids aimed at funding the Maoist revolutionary group, the Workers' Party of Scotland.
In 1973 he was given a further six years for rioting at Porterfield Prison in Inverness.
Kilmarnock Prison, the only privately-run jail in Scotland, has been at the centre of controversy over staffing levels.