Britain’s biggest cigarette company is facing questions over its links to the Belarus regime as a state-owned factory accused of fuelling smuggling produces millions of packets of its top brands each year.

The state-owned Neman Tobacco Factory in Grodno carries out production for British American Tobacco, making products such as Rothmans and Pall Mall for its domestic market.

But police seizures in the UK, analysed by i, show illicit packets bearing their logos and Belarusian health warnings were uncovered in recent raids in cities such as Hull and Sunderland.

Around 10 per cent of the 5.5 billion cigarettes sold illegally each year in the UK are estimated to have come from Belarus and experts claim most are made at the Neman factory.

There is no suggestion is BAT aware of any illicit trade and the firm said it has “strong controls” to stop its products entering the black market.

MPs and activists have questioned whether BAT and other British firms should be maintaining ties with Belarus.

A spokesperson for the pro-democracy group Nadzeya-UK said: “It is ­outrageous that a major British company continues to have a close relationship with a Belarusian plant which is 100 per cent owned by a Lukashenko regime that tortures its own people.”

Meanwhile, border and customs officials continue to try to stem the flow of illegal cigarettes originating from Belarus.

Olaf, the EU-wide counter-fraud organisation, said that Belarus was “one of the main source countries for cigarettes smuggled into the EU”.

A BAT spokesperson said: “We are satisfied that BAT Belarus applies all the relevant BAT group policies and procedures with regard to combating illicit trade to ensure that products, manufactured by GTF Neman under BAT Group’s trademarks, are consumed in the Republic of Belarus.”