James Kidd, 25, admitted having the banned item in Perth Prison in December 2017, which he had made from a spoon, a guitar string, a pen and a PlayStation controller.

Sheriff Keith O’Mahony told Kidd that he “may very well have some skills”, but urged him to “use those skills to do something more productive”, The Times reports.

However, when the sheriff handed down a three-month jail sentence for his offence, Kidd interrupted to point out that the law limited him to a maximum sentence of 30 days.

After consulting the law, Sheriff O’Mahony agreed and handed down a 20-day sentence, reduced from 25 for Kidd’s early plea, to run consecutively to his current sentence.