Toni Milton, 38, mistakenly dialled Neil O'Brien's number on her mobile phone while she was making love to her ex-boyfriend, a court heard.

O'Brien, 41, said the sound of his girlfriend sleeping with another man caused him to flip out. He drove to her house and stamped on her face so hard he left a shoeprint, Leicester crown court heard.

He was jailed for 15 months after a judge said even the "unusual circumstances" of the incident would not save him from prison.

Miss Milton only realised she had accidentally pressed the redial button on her mobile phone when she heard O'Brien shouting at her down the line. When she picked up the phone he said: "I take it we're finished then?"

The court heard the couple had been together for six months, but the relationship had hit a rocky patch. When O'Brien went to stay with his parents in Exhall, Coventry, Miss Milton invited an ex-boyfriend to her home in Barwell, Leicestershire.

John Hallissey, prosecuting, said: "It appears that while they were in bed together - and it is relevant that they were having sex - her mobile phone was knocked on to the floor.

"It landed in such a way that it dialled O'Brien's number. The first she knew of what had happened was when she heard him shouting her name."

O'Brien, who has previous convictions for violence, including grievous bodily harm, admitted a charge of assault causing actual bodily harm.

Judge William Everard told him: "Any court would understand why you were angry.

"But the fact remains you drove 15 miles and confronted this complainant - and I am satisfied you were determined to wreak your revenge. The injuries could have been fatal."