Tracy Davies: After drinks and a meal, Miss Davies became upset about the fact that her doctor had recently told her she was not pregnant Photo: PA

Mark Coghill said his seemingly loving girlfriend, Tracy Davies, suddenly "turned into the likes of Mike Tyson", chewed off half his tongue and spat it out on the floor in front of him.

The 45-year-old was rushed to hospital by ambulance but doctors were unable to stitch it back on.

Jurors were told that when police arrived at Mr Coghill's home, Davies handed officers the severed flesh in a small plastic bag and said: "We had a domestic and I bit his tongue off, here it is."

Divorcee Mr Coghill said he had been dating Miss Davies for three months when he invited her to his house to celebrate his birthday on October 10 last year.

After drinks and a meal, Miss Davies became upset about the fact that her doctor had recently told her she was not pregnant, the court heard.

Mr Coghill, of Jesmond, Newcastle upon Tyne, said he tried to comfort Miss Davies and she said to him: "You haven't given me a proper, nice, smoochie, tongue in, sort of kiss for a few days."

He said: "I had wanted to anyway but she asked me to do that.

"She was nice and beautiful and passive then within a few seconds she turned into the likes of Mike Tyson."

Mr Coghill added that within a few seconds, Miss Davies was biting hard on his tongue.

He said: "I screamed, thinking it was some kind of joke for a few seconds, then I screamed more and more and more and tried to tap her on the head.

"I couldn't kick her off or push her off or anything like that. I was just hoping and praying she would stop but she didn't.

"She had my tongue in her mouth and she went 'mmmm' as though she was satisfied.

"She looked at me straight in the eyes, she made sure I saw half of my tongue was actually in her mouth and she spat it out on the carpet.

"My immediate reaction was has this really happened, have I had some sort of nightmare? So I checked and my tongue had gone, she had actually done it."

The former customer services worker met Miss Davies in June last year after placing an advert in a local newspaper's lonely hearts column.

The court heard that the couple had sex on six occasions before the alleged attack and that Miss Davies had told Mr Coghill that she loved him.

Davies, of Gateshead, denies causing grievous bodily harm with intent and claims she does not know how the injury was caused.

The trial at Newcastle Crown Court continues.