A labourer who was cleared 15 years ago of murdering his girlfriend became the first person in British legal history to be convicted under the double jeopardy rule today.

Billy Dunlop, 42, pleaded guilty to the murder of Julie Hogg, 22, a pizza delivery girl on November 16, 1989 at the Old Bailey.

As he did, Ms Hogg’s mother, Ann Ming, who had campaigned for years for the 800-year-old law to be changed to allow a suspect to be tried twice for the same crime, wept in the well of the court.

Dunlop had faced two trials after Ms Hogg’s body was discovered behind her bath at her home in Billingham, Teesside, by her mother but was cleared by both juries after they failed to reach a verdict.

But because of a change to the law, suspects can now be tried for the same crime again if there is compelling new evidence.

Outside court Mrs Ming said: I have waited 17 years to hear him say guilty. I am just relieved."

Lord Goldsmith, the Attorney-General, who met Julie Hogg’s mother, said: "The Criminal Justice Act of 2003 brought about a significant and welcome change in our criminal justice system, by giving the Court of Appeal the power to quash an acquittal and order a retrial for a serious offence when there is new and compelling evidence relevant to the guilt of the acquitted person.

"It is in the interests of justice, and of the public, for such retrials to take place. As this verdict shows, if acquitted of a serious crime, offenders will no longer be able to escape responsibility for their act should new and compelling evidence come to light.

"At last there is justice for Julie. And for her family, especially Ann, who fought so hard for this day, even coming to Parliament to tell me why we had to change the law. She was right."

Dunlop, wearing a checked shirt and with a pony-tail scraped back, showed no emotion as the charge was read to him, that on November 16, 1989 he murdered Julie Hogg. He replied "guilty" as his victim’s mother clenched her fist, stifled a sob and wept.

The mother-of-one had been strangled and sexually assaulted.

Dunlop was always considered the prime suspect, as his hair and sweater fibres were found on Ms Hogg’s body, and traces of his semen were detected on the towel in which her body was wrapped.

Explore Law

• Columnists

• Law Panel

• Law Reports

• Student Law

Times Recommends

• BGC 'set aside £40m to lure Tullett brokers'
• Legal aid review to ensure value
• Fears as 21 magistrates' courts face closure