TRADING Standards officers have backed union plans for a compulsory warning poster to beat under-age drinkers.

Retail union Usdaw is pressing the Government to make No ID No Sale notices compulsory in all stores selling alcohol in the UK.

The plans have come about to curb the attacks on shopworkers after refusing to sell youngsters alcohol.

Refusal to sell is the trigger for about 20,000 violent assaults on shopworkers.

David Lodge, a spokesman for West Yorkshire Trading Standards Service, welcomed the plans.

"If a No ID No Sale poster is displayed prominently then people will know to not even try and buy alcohol if they are under-age," he said.

"This would stop their reactions after refusal because the situation would not even get to that."

Usdaw also said it was concerned about the number of "sting" operations run by Trading Standards.

These involve under-age youngsters attempting to buy either cigarettes or alcohol.

But Mr Lodge added: "We don't see them as sting operations - they are test purchases.

"We are responding to complaints. Before we make a test purchase we write to the retailer to warn them about the complaints.

"If nothing is done we can then follow that up.

"Also we use young people who don't look like they are old enough to buy alcohol or cigarettes.

"We try to use 14-year-olds for buying alcohol and 12-year-olds for buying cigarettes.

"These people are far too young and look under-age."

Mr Lodge added: "If shop owners follow the rules, there should be no problem."