HMP Kilmarnock is the most successful Scottish prison in reducing substance addiction.

The Ayrshire prison has achieved the best results out of the 15 Scottish prisons.

Addiction Prevalence Testing data released on the Scottish Public Health Observatory website revealed that the prison achieved a reduction of substance abuse from 91% on prisoner admission to 12% on liberation.

These scores compare with the overall performance across all Scottish prisons of 78% to 31%.

Serco contract director at HMP Kilmarnock, Michael Guy, said: "These results are down to the hard work and professionalism of everyone at the prison.

"We have a multidisciplinary approach to 'prevent, detect and educate' and it's been very effective.

"The prison's intelligence unit works with Police Scotland to 'prevent and detect', disrupting the attempted smuggling of illegal substances, including drugs, into the prison.

"This work also supports the routine and intelligence led searches in the prison."