A man who stabbed two detectives with a commando-style dagger 30 years ago has been locked up for seriously wounding a schoolgirl with a kitchen knife.

David Waterhouse, 52, was given an extended prison sentence of five years by Mr Justice Grigson at Bradford Crown Court today.

Waterhouse, of no fixed address, was convicted of wounding the 14-year-old girl on the Holme Wood estate, Bradford, in June 2006.

He was cleared by a jury in April of attempted murder and intending to cause the teenager grievous bodily harm.

The girl, who cannot be named for legal reasons, lost more than four pints of blood when Waterhouse attacked her.

The former boxer told police she was a drug user, saying: "I've done Bradford a favour."

Waterhouse, who has damage to the frontal lobes of his brain, said he had no recollection of the stabbing.

The father of four children suffered serious head injuries in a road accident in 2001.

After the attack, he texted his former partner saying: "Six more to finish." He told police he meant Bradford drug dealers.

The knife caused a wound eight inches deep that pierced the girl's diaphragm and liver.

Surgeons at Bradford Royal Infirmary carried out emergency surgery to save her life.

Mr Justice Grigson said Waterhouse stabbed his "young and defenceless" victim with considerable force after equipping himself with an eight-inch kitchen knife.

He was convicted of two offences of wounding with intent in 1978 when he used a large knife to stab two police officers who had arrested him.

The judge told Waterhouse: "A doctor, during the course of the trial, described you as a time bomb. I am entirely satisfied that you present a significant risk of serious injury to the public by the commission of specific offences."