West Berkshire Council used the underage volunteer to test whether a recent warning to retailers had been heeded, and were delighted that local shopkeepers had remained vigilant.

With violent crime on the rise in many British towns, and growing concern that alcohol is largely to blame, council inspectors are keeping up the pressure on booze outlets in the area.

Food and trading standards manager Sean Murphy said: “The retailers of alcohol are to be applauded for the steps they are now taking to ensure that they do not sell alcohol to those under eighteen.

“Over the years, we have seen a steady decline in the number of illegal sales from 50per cent of retailers selling three years ago until today.

“What officers found most encouraging was the fact that most retailers asked for proof of age. This shows that retailers are taking our advice and adopting 'no proof of age –no sale' policy."

Billy Drummond, Executive Member for Community Safety said: “The access to alcohol by young people is of concern to police, health professionals and local authorities, as well as the community at large.

“It can lead to health problems as well as anti-social and violent behaviour in our community. The results of the recent test–purchasing campaign for alcohol are very welcome and show the message is getting through.”