Lincolnshire pubs were caught out last weekend when police performed an underage spot check.
The Horse and Groom pub in Lincoln has been given an official warning and a fine for selling alcohol to young drinkers.
Pubs and clubs have been warned about the checks, and will be tightening up age checks in the coming weeks.
Duncan Watson, manager of the Horse and Groom, has been speaking to Siren FM’s Leigh Milner.
Listen to the interview