The son of Farmers Weekly columnist David Richardson is due to be released from prison, after his sentence for mistakenly importing a gun into the country was reduced by the High Court.

Andrew Richardson was jailed for three years in March 2009 after admitting possessing a firearm and ammunition at Norwich Crown Court.

He had previously lived in the USA where he had owned the gun legally. But a mix up with a shipping firm meant the gun was accidentally transported to Britain when he moved back to the UK in the 1990s.

This week the High Court ruled his case “exceptional” and slashed his sentence to 16 months, allowing for his immediate release.

Supporters of Mr Richardson have always argued that the orginal sentence seemed harsh given that he had made a genuine mistake.

The judges presiding took into account the fact he had to undergo emergency heart bypass surgery in August and that his condition may well have been worsened by his imprisonment.

“We shall be delighted to have him home, so we can help him regain his health and rebuild his life,” said David Richardson. “I would also like to thank to everyone who has written to him during this time to offer their support.”