About 300kg of tobacco has been confiscated by the UK Border Agency from a group of passengers on a Leicester-bound coach.
Customs officers discovered the tobacco on the coach as the passengers returned from Belgium on Wednesday.
The party of 79 people was stopped as the coach left a ferry at Dover.
A spokesperson said the tobacco was confiscated due to evidence that it was being brought into the UK as part of an organised attempt to avoid paying duty.
The UK Border Agency said the Treasury would have lost more than £35,000 in unpaid duty on the tobacco.
No criminal charges have been brought against the people found with the tobacco, but their names have been added to border watch lists which alert officials when suspected smugglers travel abroad.
Carole Upshall from the UK Border Agency said: "It is perfectly legitimate to shop in Europe and bring back tobacco for yourself, but anyone who smuggles tobacco for commercial gain is effectively stealing from the public purse and from law-abiding taxpayers.
"The money from this kind of smuggling is often recycled into other forms of organised crime."