AN ILLEGAL immigrant who killed a man before fleeing to the North-East where he was caught by police has been sentenced for the crime eight years later.

Restaurant worker Yi Zhong Zheng, who suffers from severe mental health problems, was unable to declare whether he was guilty to a charge of murder when he appeared at the Old Bailey in 2000.

But since he was said to pose a considerable risk to the public, he was detained under mental health legislation by the then trial judge Lord Bingham, a former Lord Chief Justice.

Yesterday, he was brought back to the Old Bailey for a fresh hearing after it was decided he was fit enough to now enter a plea - a move thought to be the first of its kind.

Chinese born Zheng, 38, yesterday denied the murder of fellow immigrant Zhen Yong Chen, 27, in June 1999, but admitted manslaughter on the grounds of diminished responsibility, a plea accepted by prosecutors.

Judge Michael Mettyear imposed a new indefinite mental health order and he was returned to a secure unit at Chase Farm Hospital, north London.

The judge declined to recommend a deportation order, saying it would be dealt with when he was finally released from detention.

Zheng had stabbed Chen with a kitchen knife as they watched television at a flat they shared with four other Chinese immigrants in Leyton, east London.

A day later he fled to Darlington, County Durham, where he was found in a telephone box by police.

He was initially arrested on suspicion of his illegal status, but officers became concerned when Zheng, who only speaks Mandarin, made stabbing motions towards himself.

He then confessed to the killing, although at that stage the body of Chen had yet to be found.

The case became a murder inquiry after the body was eventually discovered in London.

The Darlington officers had also discovered forensic evidence on Zheng, linking him to the stabbing.

At the time the team involved - Detective Inspector Ian Phillips, Detective Sergeant Mick Wilson, Detective Constables Malcolm Lear and David Kyle and PC Karen Jones - were praised for their efforts to trap Zheng.

They were able to furnish officers from the Metropolitan police with a complete package of forensic evidence, when they travelled up to collect the Chinese immigrant and take him back to the capital.

Speaking in April 2000, Det Insp Phillips, who has since retired, said: "This was one of the more unusual cases I have dealt with which started off as a routine inquiry about an illegal immigrant and ended up with our involvement in a murder inquiry."