SHOPKEEPERS have been banned from selling tobacco products to customers aged under 18 in a law that comes into force today.

Some retailers are concerned that the legislation, which raises the legal age from 16, will cause friction with young customers.

The law comes at a time when the Government says that someone who starts smoking at 15 is three times as likely to die from cancer due to smoking than someone who starts in their mid-20s.

Ailsa Rutter, director of the Fresh - Smoke Free North-East pressure group, wants the law to go further and would like to see a ban on cigarette vending machines and all tobacco products placed out of sight in shops.

She said: "We know that children often obtain cigarettes from vending machines.

"Steps must be taken to address this and also the unnecessarily high levels of point-of-sale advertising, which acts as an incitement to children to start smoking. There should be no vending machines and all tobacco products should be under the counter."

A spokesman for the British Retail Consortium said: "Cigarettes are already behind the counter and customers have to ask for them. It is hard to see what difference it would make if the product is not visible to the customer."

He expressed concern that many 16 and 17-year-olds may be unaware of the new age limit and stores could become flashpoints for abuse.

One Darlington newsagent, who wished to remain anonymous, said: "I get a lot of abuse as it is when I ask a 16-year-old for ID and I can see a lot more coming my way because of this. I will have to turn people away that I have been serving previously.

"Because it hasn't been very well publicised, a lot of people simply aren't aware the ban is coming into force."

Julie Addison, of Addison newsagents, in Stockton, said: "It used to be a lot easier to tell who was under-age and who wasn't, but with this change it is going to become more difficult. I think a lot of shopkeepers could be caught out by people who look about 18.

"Hopefully, when we have to ask people to prove their age they won't become angry or aggressive."

James Lowman, chief executive of the Association of Convenience Stores, which represents 33,000 local shops, said: ''The risk that low awareness presents is that people will blame the retailer for refusing to sell them a product they were previously able to buy. This will lead to flashpoints, abuse, intimidation and even violence.''

* Pub, bar and restaurant workers' exposure to second-hand smoke has fallen by 95 per cent since smoke-free workplaces were introduced in July, according to the National Cancer Research Institute Conference, in Birmingham.

Researchers assessed air quality in almost 40 venues, 15 per cent of them in the region.