Licensees have been warned against passing off inferior spirits as branded names after one restaurant was ordered to pay fines and costs of £3,964.
Brent & Harrow Trading Standards found two spirits at an un-named restaurant were not genuine. The venue was fines £2,500, plus costs of £1,464.
The International Federation of Spirits Producers (IFSP) said many licensees are still unaware that refilling bottles, even with the same brand, is illegal and brand substitution can lead to loss of licence.
"There's an important additional risk to be considered, that of losing business due to a tarnished reputation," said Philip Scatchard, director of the IFSP UK.
"The recession has made things very competitive for bars and restaurants; with consumers mindful of their spending and looking for value for money.
"Many local authorities are conducting similar campaigns to stamp out this practice across the UK and with instances of substitution such as this frequently getting into local and national press, it's really not worth it, as the outcome can be extremely costly."
The head of Trading Standards for the London Boroughs of Brent & Harrow added: "This Service won't hesitate in instituting legal proceedings in cases where the interests of consumers and legitimate businesses are being harmed."