WHEN a teenage transsexual killed his homosexual boyfriend he was suffering from an abnormality of mind, a court has heard.

Psychiatrist Aideen O Halloran said Karen Lawson, who has changed his name by deed poll from Mark Lawson, was suffering from Gender Identity Disorder

Lawson, who denies murder, is said to have confessed that he had been troubled about his sexuality since his school days.

The 19-year-old was arrested in Hartlepool three weeks after the body of lover Michael Cutler, also originally from the town, was found at the flat they shared in Greater Manchester last March.

Dr O Halloran told the jury at Manchester Crown Court: It is an abnormality which could impair responsibility for his acts. It is sufficient, but whether it impaired his responsibility for his actions when his partner died is, I believe, a matter for the jury to decide.

Dr O Halloran said Lawson saw himself as a woman while having the body of a man. It had troubled him for some years.

Lawson claimed he snapped during a bedroom row in which Mr Cutler withdrew his support for his planned sex change operation and assaulted him.

Dr O Halloran, a prosecution witness, said Lawson told her he had been troubled about his sexuality since his school days.

He had wanted to use nail varnish and to buy and wear female clothing. He was considering a sex change at that time.

His stepfather had strongly objected, "believing he could physically beat it out of him."

Lawson claimed he was bullied at school about his feelings and alleged his stepdad also forced him to have tattoos on his arms and back.

The accused was aware of sex change possibilities and was unhappy about puberty and the development of his private parts.

There was a sexual relationship with Mr Cutler which Lawson said he did not enjoy. His partner did not like him to wear female clothing.

They went together to a sex clinic in Manchester, but on the night of the killing they had a row.

His partner was refusing to fund the operation and also said if Lawson loved him he would not go ahead with it.

The doctor said Lawson claimed to have been physically assaulted before he snapped and launched himself at Mr Cutler, 43, whose body was later found in the utility room. It was so badly decomposed the cause of death could not be ascertained.

But when Lawson was arrested he confessed to suffocating and strangling his partner.

Answering Vera Baird QC, defending, the doctor said it was clear the wish for surgery had become very central to Lawson.

The Gender Identity Disorder was a significant factor in his claimed loss of control following provocation before the killing.

I do not think he would have responded as he did without the abnormality of mind he had and still has, she said.

Mr Cutler lived for many years at Turnbull Street, Hartlepool; and Lawson, of Stainton Grove, Barnard Castle, had moved to The Front at Seaton Carew between the time of the killing and his arrest.