The 78-year-old woman tried to sue Iorworth Hoare after he won the lottery in 2004, but was unsuccessful because the sex attack happened 19 years ago.

The unanimous ruling backed Mrs A and people featured in four other sexual abuses cases, some involving children. It is expected to pave the way for thousands of victims to pursue claims for damages many years after their abuse.

The five cases considered by the law lords were sent back to the high court to be reconsidered in light of today's ruling.

The law lords ruled that claims for sexual assault should be brought within three years in future - in line with other civil claims for damages - but said courts should have the discretion to extend the period to permit older claims, removing the six-year cut-off point.

In a statement read by solicitor Sandra Baker, Mrs A said she hoped her compensation claim could now be speedily settled at the high court.

"I am both delighted and relieved that my appeal to the House of Lords has been successful and that I have succeeded in changing a law which will provide others in the future with a means of achieving justice," she said. "It was this, rather than financial gain, which motivated me to begin this process two years ago.

"It is to be hoped that my claim for damages against Iorwoth Hoare will now be brought to a speedy resolution without the need for me to endure further protracted litigation.

"I hope that many others in the future will be able to benefit from the change in the law which I helped to bring about."

The charity Victim Support welcomed the ruling but said it would help few people. Its spokesman, Paul Fawcett, said: "It's very good news for her but the wider significance is questionable because the vast majority of offenders don't have assets to chase.

"We have long campaigned for a public fund to allow the courts to award compensation, leaving it to the courts to recover assets from the offender and allowing the victim to walk away and put the crime behind them."

Mrs A lost her case in the high court and court of appeal, and was ordered to pay Hoare's £100,000 legal costs. Her case was one of five appeals heard at the House of Lords on how the Limitation Act affected claims in abuse cases.

Mrs A, who received £5,000 from the Criminal Injuries Compensation Board, sought compensation from Hoare for psychiatric injury caused by the "violent and disgusting" attempted rape in February 1988.

Hoare, 59, who had subjected six other women to serious sexual assaults, including rape, attacked her as she walked in Roundhay Park, Leeds, West Yorkshire. The retired teacher says she still suffers from nightmares and claims the brutality of the attack destroyed her self-esteem, wrecked her relationships and ruined her life.

Hoare had not been worth suing until he won £7m. He was jailed for life in 1989 and spent 16 years in prison before buying the winning Lotto Extra ticket while on day release. He was released in 2005 and is reported to live in a £700,000 house near Newcastle.