Now aged 21, Ferris immediately returned to his work as an enforcer for Thompson, and was soon arrested again and charged with possession of offensive weapons after a pickaxe handle and knives were found in his car. While awaiting trial he was involved in a stabbing, and fled to Thompson's holiday home in Rothesay on the Isle of Bute. Within a day of arriving there, he was arrested by armed police and charged with various offences including attempted murder and possession of heroin with intent to supply, and was remanded to HM Prison Barlinnie. The attempted murder charge was dropped a week later and Ferris was found not guilty of the drugs charge, but he received an 18-month sentence for possession of offensive weapons. After being released from prison Ferris stopped working for Thompson and started a company named Cottage Conservatories specialising in double glazing and conservatories, but still remained active in the criminal underworld.