A secret tunnel containing more than 148,000 illegal cigarettes were uncovered in a police raid found thanks to cocker spaniels.

Police visited eight shops across Gravesham on Monday and Tuesday to tackle the sale of illicit cigarettes and tobacco.

During the operation, they seized 242,500 cigarettes and 1,516 pouches of tobacco. The haul is thought to be worth an estimated street value of £76,000.

They worked with staff from Gravesham council, Kent Trading Standards, HMRC and the Home Office Immigration Enforcement team to carry out the raid.

Specialist detection dogs were also sent out with Bran, a working cocker spaniel, indicating there was tobacco behind some tiling in a basement.

Officers removed the false panel and found a tunnel had been dug through to the basement of the adjoining shop.

Inside officers found more than 148,000 cigarettes and 1,315 pouches of tobacco, the largest single seizure the team has secured.

In another premises, they found a makeshift chute behind a counter and followed it up to a second floor flat.

Yoyo, also a working cocker spaniel, gave the indication there was tobacco inside so officers forced entry.

Inside the flat, they found 58,900 illicit cigarettes and 135 pouches of tobacco hidden behind magnetic concealments inside three false walls.

Inspector James Beautridge of North Kent’s community safety unit said: "The results from these two days shows just how prevalent this issue is, and the lengths to which some shop owners will go in order to hide these products and avoid detection.

"The sale of illicit cigarettes and tobacco poses a serious health risk to consumers and also hinders law abiding businesses.

"Regulations are in place to ensure that the tobacco products consumed on a daily basis are as safe as possible and do not contain unregulated ingredients.

"Kent Police is determined to work with our partner agencies to stamp out the illegal sale of unregulated tobacco and hold offenders to account for their behaviour which is why operations such as this one are so important."

During the operation illegal vapes were also seized and fines were issued for immigration offences.

Tano Grima, assistant director of south east immigration enforcement said: "This is a great result and shows the vital role immigration enforcement plays in tackling crime.

"These people are not only breaking the law and defrauding the public purse, they may also be vulnerable to exploitation because they do not have the same protections as those who work here legally.

"We are committed to safeguarding people at risk of modern slavery and are pleased to be a part of this targeted, joined-up approach."