Customs officials are cracking down on a new breed of website which claims to offer imported cigarettes and tobacco at cheap prices.
The websites offer consumers the chance to buy the products at cheaper duty rates than in the UK and the fear is that they may extend to alcohol and cause problems for the pub trade.
One internet site, Cheap Cigarettes UK, claims: "Legally import cigarettes and tobacco from Spain into the UK - all the top brands available."
The sites are cropping up following the Chancellor's duty rise on beer and cigarettes last month. But Customs and Excise has warned consumers that UK duty must be paid on any goods posted from Europe. If there is any doubt, goods will be seized at postal depots.
However, new proposals being debated by the EU could open the floodgates for UK consumers to buy alcohol and tobacco over the internet at the lowest duty rates in Europe.
If new "distance selling" regulations are approved, it would mean that duty on goods bought over the internet within the EU would be paid at the rate in the country where they are sold.
Mark Hastings, spokesperson for the British Beer & Pub Association, said the rules would allow a UK consumer to order cases of beer from countries such as Spain, where beer duty is around a tenth that of the UK.
He said: "This undermines the government's entire stance on maintaining higher duty levels."
UK customs officials have been acting to shut down websites which sell cheap cigarettes from EU states to British consumers.
A spokesman said: "Customs is well aware of these sites and we are vigorously pursuing action against them. Our officers at postal depots are actively targeting importations of cigarettes."
Regulations say that duty and VAT must be paid on all items bought over the internet and imported into the UK. In the mid-1990s the Enlightened Tobacco Company lost a test case in the European Court after it set up a mail order business importing cigarettes from Luxembourg.
The long court battle ended with a ruling that consumers can only avoid paying UK duty if they physically import goods themselves.