Smokers in an Ulster town were puffing more illegal cigarettes than anyone else in the UK at the end of last year, research has found.
Two out of every three packs bought in Newtownabbey between October and December originated from the black market, according to the study.
Lisburn ranked second in the UK-wide survey commissioned by tobacco manufacturer Philip Morris, with 43% of cigarettes consumed in the city coming from illicit sources.
Crawley (31.6%), Coventry (30.3%) and London (28.5%) were the next three ranked in the top five.
Criminal gangs are known to target a town or city and flood it with illicit packets before moving their racket to the next location. This could account for the high levels in Newtownabbey and Lisburn last year.
The Exchequer loses millions every year as a result of duty evasion on black market tobacco.
According to the analysis of the last quarter of 2011, the problem is on the rise.
Almost 15% of cigarettes smoked across the UK between October and December did not have duty paid, compared with just over 10% in the previous three months.
The illicit trade includes counterfeit and genuine cigarettes smuggled into the UK without paying tax and ones manufactured and sold in the country without telling the taxman.
Counterfeits of UK cigarette brands are manufactured mainly in the Far East, with China one of the primary sources.
The study did not include hand-rolled tobacco, around half of which consumed in the UK each year is estimated to be from the black market.
Will O'Reilly, a retired detective chief inspector from Scotland Yard, warned smokers to be wary of cheap packets.
"The same networks who have historically dealt in hard drugs, illegal firearms, people trafficking and terrorism are now funding and organising this illicit trade," he said.
"For them this is a growing source of income with much lower risk and the penalties, if caught, are in comparison minor.
"If you buy a cheap packet of cigarettes that money ends up supporting organised crime. Every cigarette funds the availability of drugs on our streets or gun crime or terrorist attacks. That's without questioning what dangerous substances could be in them."