The sting was part of a crackdown led by the authority's trading standards office.

Undercover teens worked with officers to help smoke out retailers making underage sales.

The results of the crackdown were published yesterday to mark national no smoking day.

It stated out of 16 attempts to purchase tobacco, three sellers failed to ask for proof of age — a failure rate of 20 per cent.

Of the three that failed, two were in Eastwood and one in Barrhead. The shops, which are not being named, were issued warning letters.

East Ren trading standards boss Steve Fox said this was both good and bad news.

He said: "We made the visits on Saturdays because we know shops are more likely to employ part-time staff then who may not have been properly trained.

"On the plus side we noted more premises are now making use of refusal books to record when and why they refused to make a sale.

"The council is committed to reducing the harm to health that smoking causes".

Staff at the stores who failed have also agreed to undergo additional training.

Mr Fox added: "Trading standards will continue to educate traders notto sell to under-18s and we will also continue to test purchase using our young volunteers and will prosecute where necessary.

"Anyone concerned a retailer may be selling tobacco to under-18s can call 577 3782".

Trading standards bosses will repeat the exercise in the next three months.

Retailers who have already received a warning letter will be reported to the Procurator Fiscal if they are caught again making an under-age sale.

NHS Greater Glasgow and Clyde director of public health Dr Linda de Caestecker said: "Cutting smoking levels is one of NHSGGC's top priorities.

"Around 29% of deaths at all ages are attributable to smoking and here in GGC we have more smokers than the Scottish average.
"It's absolutely vital we make it as easy as possible for people to give up".