Human trafficking is an evil trade and victims of modern slavery are often compelled to engage in criminal activities on their arrival in Britain.

A Court of Appeal ruling, however, showed that judges are far from blind to such grim realities.

The case concerned a Vietnamese national who was arrested following a police raid on a house that was being used to cultivate cannabis on a substantial scale. He explained that he had been smuggled into Britain on the back of a lorry and compelled to farm cannabis by two men of whom he was terrified.

He said that he had been living in the house for over four months, had nowhere else to go and was too scared to leave. He was nevertheless prosecuted and sentenced to 12 months’ imprisonment after he pleaded guilty to producing a controlled drug contrary to the Misuse of Drugs Act 1971.

Ruling on his appeal against his conviction, the Court noted that, by Section 45 of the Modern Slavery Act 2015, a person is not guilty of an offence if he commits what would otherwise be a criminal act under compulsion attributable to slavery which gives him no realistic alternative.

The man presented fresh evidence in the form of a Home Office decision that there were reasonable grounds to believe that he was a trafficking victim. In the highly unusual circumstances, the Court took the exceptional step of vacating his guilty plea and quashing his conviction.