Two licensees have been fined after routine Trading Standards inspections found them guilty of substituting leading spirits brands.
Magistrates issued awards of fines and costs against the licensees of Freddy's Bar and Restaurant in Harrow and at Kolize Pizzeria in Hedon, Yorkshire amounting to more than £4,000 and £6,500 respectively.
Trading Standards authorities say licensees need to be aware of the laws and regulations, refilling bottles for resale, even with the same brand, is illegal.
Philip Scatchard, director of the International Federation of Spirits Producers UK, said: "Across the country local authorities and Trading Standards are heavily involved in preventing this practice and making sure that consumers get a fair deal. Officers are visiting premises by way of routine, as well as following up tip-offs or complaints raised by members of the public."
He added: "Cases such as these can get into the consumer press and when times are hard for many licensed businesses, such incidents, although carried out by a small minority of licensees can be damaging to the whole trade."