Retailers who repeatedly sell cigarettes to under-18s will be banned from selling tobacco products for up to a year with the introduction of a 'negative licensing' scheme in 2008.

In the government's toughest- ever clampdown on underage sales, store owners will not be required to apply for a licence, but will have the right to sell tobacco taken away if they fail three or more test purchasing stings in a two-year period.

The severity of the bans, which can apply to shop staff as well as to the premises, will be decided by magistrates on a case-by-case basis, with the length of the ban proportionate to the offence. They could be as short as a day, or as long as a year. Failure to comply could result in fines of up to £20,000.

The Department of Health (DoH) expects the system to be in force by October 2008, having been appended to the Criminal Justice and Immigration Bill which is currently before parliament. Details of its workings were revealed in a letter from the DoH to councils.

The Association of Convenience Stores (ACS) said it was deeply concerned with how the system would be implemented. 

"We are very worried about the implications that tobacco trading bans would have on retailers," said Shane Brennan, ACS public affairs and communications manager. "Even the largest convenience store would struggle to continue trading if banned from selling tobacco for one year."

The laws on tobacco were "deeply unfair", he added, saying that the ACS would continue its fight to make proxy purchasing and buying tobacco under the age of 18 illegal. 

"The fact that it is illegal for retailers to sell tobacco to underaged persons, but not for underaged persons to buy it, is wrong. If the government is to introduce this new negative licensing scheme, then we want other amendments made to make the law fairer," he said. 

The government shelved the idea of a positive licensing scheme after consultation revealed that it would be too costly to implement.