Some 10,000 illegal cigarettes were seized at a Lincoln High Street shop as part of a joint operation between Lincolnshire Police and Trading Standards.
The operation targeted Baltic Mini Market on Wednesday, March 3, where counterfeit and untaxed cigarettes were hidden behind a brick wall.
Police said this was no match for their sniffer dog though.
The cigarettes are suspected to be counterfeit, meaning they are not duty paid and do not meet safety regulations.
They are also not labelled according to regulation.
Police said there have been no arrests at this stage and the shop is still able to trade at present.
Andy Wright, Principal Trading Standards Officer at Lincolnshire County Council, said: “This was a good find in the battle against illegal tobacco in Lincolnshire.
“Some people might think that there’s little harm in buying these cheap cigarettes, but the illicit tobacco trade funds organised crime and the products for sale are often dangerous knock-offs.
“Criminals will go to great lengths to try and conceal their illegal activities; our officers found these cigarettes in a yard at the back of the premises, in a hollow in a brick wall.
“Anyone with information about the sale of illegal cigarettes and tobacco in Lincolnshire can report it anonymously through CrimeStoppers by calling 0800 555 111 or through crimestoppers-uk.org.”