A woman at the centre of a supermarket row over queue-jumping that led to the death of an innocent shopper has been found guilty of manslaughter.

Antoinette Richardson, 37, from Catford southeast London, had been shopping in Sainsbury's in Merton last June when she became involved in a heated argument with a man.

She telephoned her boyfriend, Tony Virasami, 38, who arrived moments later and punched Kevin Tripp, 57, who later died from the blow.

Tripp however was not the man with whom Richardson had been arguing.

"As they came off an escalator, she pointed out the man she thought she had been arguing with and told Virasami: 'That's him,'" the Metropolitan police said in a statement.

Tripp, an ME sufferer from Colliers Wood, south London, died from a single blow to the head. He leaves a five-year-old daughter.

Richardson, who protested her innocence in court on Thursday, and her boyfriend will be sentenced at a later date. Virasami pleaded guilty to a charge of manslaughter last year.

Richardson maintained she was as shocked as anyone else at the turn of events, the Press Association reported.

"I was shouting 'no', trying to shout 'stop, what are you doing'" the court heard.

But the prosecution contended that she was more interested in pursuing the person she had rowed with than admitting her mistake and tending to the fatally injured Tripp.

As the 11-1 majority verdict was announced, Richardson bowed her head slightly and closed her eyes.

Shouts of "yes", and a celebratory shaking of fists came from members of her victim's family.

"The death of Kevin Tripp has devastated his family," said Detective Inspector Bob Campany from the Homicide and Serious Crime Command after the hearing.

"Virasami's reckless actions represent a spectacular over-reaction. They can in no way be justified even if Kevin had been the man who offended Richardson.

"The fact that he wasn't makes it even more reprehensible."