The father of a 14-year-old boy who was killed crossing a road after drinking cans of lager is hoping to succeed in his crusade to close a legal loophole next week.

John Knowles is hoping that the House of Lords will give its assent on Tuesday to a Bill making it possible to prosecute off-licence staff who sell alcohol to under-18s.

If the Lords grant their approval it will end a three-year-long battle by Mr Knowles and Pudsey MP Paul Truswell to close the loophole which allowed staff who sold drink to Mr Knowles's son David twice in five minutes to escape prosecution.

He was killed running across the Stanningley bypass after being served alcohol twice by staff at the Drinks Cabin off-licence, in Market Place, Pudsey in March 1997.

"If it is passed on Tuesday then I believe it effectively becomes law. It will be the end of a long saga for us," said Mr Knowles.

"It will mean that people who run establishments selling alcohol will be responsible for their actions."

He added: "It will close the loophole which should have been done a long time ago and it will give protection to the youngsters.

"It's been three years since I walked into Paul Truswell's office to see what could be done but we're finally going to make a difference."

The loophole in the 1964 Licensing Act is that only the licensee or people directly employed by him can be prosecuted for selling to under-age customers.

In David's case the staff were employed by a national company and not directly by the licensee.

The Bill, which Mr Truswell has labelled "David's Law" has been sponsored through Parliament by him as a Private Members Bill.

He said: "I could not believe that the law governing the sale of alcohol to young people had such a massive loophole in it until John Knowles brought it to my attention.

"I gave John and his family a commitment that I would do all I could to close the loophole - not only as his MP, but also as a parent myself."

Mr Knowles said he hoped to be in the House of Lords when the Bill is given its final reading.