Three out of seven Bradford off-licences targeted in a trading standards sting sold alcohol to children.

Although the only shops tested were those which the public had complained about, the statistic has shocked standards officers who had expected a figure closer to 10 per cent.

The three-month blitz was part of a nationwide Home Office initiative to crack down on teenage drinking.

After complaints, West Yorkshire Trading Standards organised for a trained youngster to try to buy alcohol in seven visits to off-licences. Three attempts - 43 per cent - resulted in alcohol being bought. The figure for the whole of West Yorkshire was 21 per cent.

Graham Hebblethwaite, divisional officer for trading standards, said: "I was expecting no more than 10 per cent - though we always strive to get no sales.

"But this was direct enforcement against premises about which there had been complaints. I would not expect such a high hit-rate if they had been random inspections."

Mr Hebblethwaite said all of the offenders now face prosecution: "All will be the subject of prosecution reports. This is a battle we are still looking to win," he said.

"This campaign has highlighted that there will be a lot of businesses across West Yorkshire which are now facing prosecution as a result. This is a significant deterrent. Not only can people be fined, they can lose their licences to sell alcohol."

He said many store owners try to excuse their behaviour but, he said, there is no excuse for selling alcohol to children: "Most of the time they say it is an oversight - carelessness - they say they were distracted or were not paying attention.

"Sometimes they say they thought the child was 18. But our team goes to great lengths to choose children who are around 14 and look it. Many storekeepers prove this by refusing to serve the child or asking their age."

Councillor Malcolm Slater, chairman of West Yorkshire Joint Services, which oversees the work of trading standards, said parents need to take more responsibility for their children's behaviour.

He said: "This problem is sometimes down to poor parenting skills. The whole community needs to make an effort to eradicate underage drinking."