The sophisticated factory, capable of evading millions of pounds of duty per year, was uncovered in an operation by HM Revenue and Customs (HMRC) and Police Scotland.

The set up included expensive machinery and insulation to hide noise and smells, with four tonnes of tobacco recovered, worth an estimated £1 million in unpaid duty.

Suspected counterfeit tobacco pouches were also found and seized.

One of Scotland’s biggest and most sophisticated illegal tobacco factories has been dismantled after a raid in West Lothian.

Joe Hendry, Assistant Director, Fraud Investigation Service, HMRC, said: “This was one of the largest and most sophisticated tobacco factories we have ever uncovered in Scotland.

“The illicit tobacco trade steals money from our vital public services, undercuts legitimate businesses and can fund other crimes that harm our communities.

“We encourage anyone with information about the illegal sale of tobacco or alcohol to report it to HMRC online.”

Detective Sergeant John Irvine, Police Scotland, said: "We will continue to work closely with our partners to disrupt, detect and deter anyone involved in the illicit trade of illegal or counterfeit cigarettes and tobacco.

"We know that due to perceived higher profit margins, criminals can turn to the illicit trade in tobacco, which in turn can lead to other forms of criminality.

“If you have any information or concerns about illegal or counterfeit cigarettes or tobacco within the local community, please get in touch with HMRC or Police Scotland. Alternatively calls can be made to Crimestoppers on 0800 555 111 where anonymity can be maintained.”

Five people have been arrested and charged. Investigations are ongoing.

Scotland's biggest illegal tobacco factory dismantled following raid in West Lothian