A severely disabled patient died after a routine operation when a surgeon "guessed" how much local anaesthetic to give him, a court heard yesterday.

Muscular dystrophy sufferer Andrew Ryan, 20, who weighed less than four stone, died after being administered more than three times the recommended dose for someone of his weight, Newcastle Crown Court heard.

Locum surgeon Praven Patel, 52, denies committing manslaughter by gross negligence at Shotley Bridge Hospital, near Consett, County Durham, in 1997.

The jury was told that Mr Patel, who has now retired, guessed his patient's weight, rather than measure it himself or refer to Mr Ryan's specialists.

As a result of the overdose, said Jeremy Hill-Baker, prosecuting, Mr Ryan had convulsions, then suffered breathing problems before he died of a heart attack.

Mr Hill-Baker said the defendant did not intend to kill Mr Ryan, or cause him injury.

He told the court: "What he did amounted to breach of his duty of care to his patient. He was grossly negligent."

Although Mr Ryan, who lived with his parents, John and Jean, on the outskirts of Durham, had lost a lot of weight, he was expected to enjoy several more years of life, said Mr Hill-Baker.

The jury heard that Mr Patel, of Harrow, north-west London, told an inquest in 1999 he had estimated Mr Ryan's weight as being 40 to 50 kilograms.

But Mr Hill-Baker told the court yesterday Mr Ryan was only 21 kilograms when he was last weighed in 1996, and his mother was sure he had not gained any weight between then and the operation.

The case continues.