A cheating boyfriend attacked his girlfriend and smashed her computer after she learned about his affair on Facebook.

Christopher Kelly, 44, was seen on webcam attacking the screen with a hammer because the victim's 15-year-old son was online when he went berserk at his home.

Kelly "behaved like a complete lunatic" after his girlfriend Nicola Smith used Facebook to uncover his infidelity, Exeter Crown Court was told.

A judge told him he escaped jail "by the skin of his teeth" after he was sent on a course to address his domestic violence.

Kelly, of Dornafield Drive, Ipplepen, near Newton Abbot, admitted actual bodily harm and criminal damage and was jailed for 26 weeks, suspended for two years and ordered to undertake 18 months' supervision, which will include a domestic abuse programme.

Judge Barry Cotter, QC, told him: "You behaved like a complete lunatic. You lost all control and punched Nicola Smith in the face.

"You struck the computer with a hammer and the effect on her and her son are aggravating features. The impact of this happening in their own home cannot be understated.

"You have a real propensity for serious violence and are a volatile character but society is best served by you addressing this as far as possible."

Howard Phillips, prosecuting, said Kelly and Miss Smith had lived together for four years and had a 15-month-old daughter together. She also had older children from an earlier relationship.

He said: "It had been a volatile relationship. In September she discovered through Facebook he had been unfaithful and there was a confrontation. He went out drinking and came back after four pints and a further argument developed.

"He then went over and punched her in the face.

"He then turned his attention to her 15-year-old son who was upstairs on the computer with a web cam talking to his girlfriend, whose mother saw him on the screen with the hammer.

"He produced a hammer and attacked the computer screen while shouting threats. Then his behaviour changed again. He took his baby daughter in his arms and burst into tears."

Niall Brooks, defending, said the victim was standing by Kelly, who has cut down on his use of cannabis and was now keen to address his violent behaviour.

He said: "He is very devastated by what he has done and very remorseful."