The 2018 Illegal Tobacco Products Research Survey, conducted by Ipsos MRBI for Revenue and the HSE National Tobacco Control Office, found that 13 per cent of the packs held by smokers surveyed are classified as illegal.

A further nine per cent of the packs were found to be legal Non-Irish Duty Paid, usually purchased legally abroad.

The survey found that 21 per cent of roll-your-own packs held by smokers are illegal, with a further seven per cent being legal Non-Irish Duty Paid.

The results for cigarettes are unchanged on 2017, but the illegal market share for roll-your-own packs increased from 15 per cent.

According to the Revenue’s annual report for 2018, over €42 million in illicit tobacco products were seized last year.

This included the detection and closure of the first-ever illegal cigarette factory in Ireland, where over 23 million cigarettes were discovered.