Former professional boxer Graham Brett has been jailed for seven years for the manslaughter of Neil Hannah. Picture: Metropolitan Police

A former professional boxer who killed a stranger with one punch outside a Pimlico pub has been jailed.

Neil Hannah died after being punched unconscious outside the Greyhound pub in Hugh Street, Pimlico. Picture: Metropolitan Police

Graham Brett, 50, pleaded guilty to the manslaughter of Australian-born Neil Hannah.

Mr Hannah was felled with one punch to his jaw outside the Greyhound in Hugh Street. He was knocked unconscious and suffered a brain injury from falling backwards.

The 49-year-old died five days after the attack on August 7 last year, the Old Bailey heard.

Brett, of Ebury Bridge Road, Pimlico, had been drinking in the Greyhound when he took exception to Mr Hannah and called him outside.

He took off his glasses and aimed a right hook at Mr Hannah, who was described as a “gentle giant” and “jovial drunk”.

Brett, who had two wins and two losses in his career, and 70 amateur fights, had drunk seven pints and taken cocaine.

Gillian Etherton QC, prosecuting, said CCTV showed the incident.

She added: “It is very clear the stance the defendant takes is one of an experienced boxer.”

Gareth Morley, defending, said Brett’s career ended in 1984 and had been ravaged by his alcohol problem, although he was still a coach for amateur boxers.

Judge Mr Justice Stuart-Smith said three years of the extended sentence would be served in the community.

He told Brett: “You are a trained boxer. You used that training to position yourself and deliver the punch. This was an unprovoked attack.”