New figures show the city ahead of Chorley and the Ribble Valley in observing the law on selling to under-18s across Lancashire.

In these areas, one in five underage smokers are served tobacco.

The results come from 300 sting operations carried out across the county from April 2007 to March 2008.

Lancashire Trading Standards officer David Johnnie said: "I think the figures should be put in context in Lancashire as we have had a reasonable amount of compliance."

The county as a whole met its target, with 92% of traders keeping to the rules and not selling tobacco to children under 18.

Trading Standards said it will give offenders a second chance by offering an "age restricted product" course.

But if traders re-offend or fail to show, they could face prosecution.

Mr Johnnie added: "They get one opportunity to attend the course. If they were to fail again, we will look to take stronger action."

The maximum penalty is a £2,500 fine and the Department of Health is looking at banning premises from selling tobacco for one year.

In 2007/08, there were three operations leading to three purchases in Preston from 19 attempts. In the Ribble Valley and Chorley, there were two from 10 attempts.

The best traders were in South Ribble, Wyre and Pendle, where no underage customers were served.