Horace Campbell (left), 28, and Liam Douglas-O'Callaghan (right), 18, were found guilty of murdering Devon Scarlett

Two men have been given life sentences for shooting a stranger dead after a row in a queue at McDonald’s in Brixton, south London.

Devon Scarlett was killed after a row in a queue at McDonald's

Horace Campbell, 28, and Liam Douglas-O’Callaghan, 18, were found guilty of murdering Devon Scarlett, 32.

Old Bailey judge Richard Hawkins said a “trivial argument” had escalated in half-an-hour to the execution of the father of four.

He jailed Campbell for life with a minimum term of 32 years. Douglas-O’Callaghan was ordered to be detained with a minimum term of 18 years.

Judge Hawkins told them: “The two of you quickly despatched Devon Scarlett without mercy.”

Mr Scarlett and Campbell got into an early morning spat involving others at the fast-food restaurant in April last year.

They were escorted outside by security guards but the row carried on and the two strangers agreed to meet in a nearby street for a shoot-out, said Bobbie Cheema, prosecuting.

Campbell called Douglas-O’Callaghan to bring his “thing”, or gun, a retrial was told.

Mr Scarlett appeared to make a similar call but no actual call was made.

Miss Cheema said: “Horace Campbell was determined to avenge the perceived lack of respect that Devon Scarlett showed him.

“Devon Scarlett acted with foolish bravado, behaving like a tough guy, but whatever he said and did, he was not armed.”

Campbell, who had been drinking, followed Mr Scarlett into Marcus Garvey Way and fired three shots, two of them hitting the victim.

Campbell said: “You are not so hot now”, before walking away.

Mr Scarlett, of Croydon, who was born Raymond Mitchell, died a few hours later in hospital.

Campbell, of Anerley, and Douglas-O’Callaghan, of Tulse Hill, both south London, denied murder.

Detective Inspector Henry Lindsley said: “Unbelievably, Devon Scarlett’s murder was triggered by the most minor of incidents that Horace Campbell chose to involve himself in.

“His arrogance and obvious disregard for life is evident when, even after Mr Scarlett walked away from him, he continued spoiling for a fight.”