A massive illegal cigarette factory located in a former pet hotel in Arlon, Belgium, has been taken out of commission, with four tonnes of tobacco and 2m counterfeit cigarettes seized by customs officers.

The operation resulted in the arrests of 14 people, mainly from Eastern Europe, who are suspected of supplying illegal cigarettes to the black market in France and the UK. An additional 40m counterfeit cigarettes – thought to be manufactured at the Arlon unit – were seized in trailers in an industrial area in Duffel.

French customs were also involved in the investigation, seized more than 25 tonnes of fake cigarettes and 16 tonnes of tobacco belonging to the same organised crime group across the border in the city of La Longueville.

The organised crime group under investigation is involved in the large-scale production and distribution of counterfeit cigarettes, said Europol, which assisted in the operation. A number of investigations are ongoing against them in several European countries.

Last year, Belgian customs arrested 40 people and seized tens of millions of counterfeit cigarettes, including knock-offs of Marlboro, Richmond, Prince and Regina brands, in an operation that targeted 10 different production sites.

A study published in 2020 by KPMG – commissioned by tobacco giant Philip Morris International (PMI) – showed that consumption of illicit cigarettes in the EU fell below 8 per cent of total cigarette use in 2019, but was still equivalent to nearly 39bn smokes and €9.5bn in lost tax revenues.

It also suggested that imports of illicit cigarettes from non-EU countries such as Ukraine and Belarus declined in 2019, with "increasing volumes from illegal factories within the EU."

Europol said the tax loss to the Belgian operation from the activities taken down in the latest operation is estimated at around €20m.