The owner of a bar who claimed customers caught smoking indoors were simply testing out a shisha pipe before buying one has been ordered to pay more than £5,000 by a court.

Gurjot Patwalia said the Boudoir shisha bar in Maida Vale, north west London, should be treated in the same way as a humidor room.

A loophole allows indoor smoking at specialist tobacconists, like those selling cigars, to allow potential buyers to sample items before purchasing them.

His defence, in a case brought by Westminster City Council, was thrown out, however, and Patwalia, 30, was found guilty on four counts of not preventing smoking in a smoke-free place.

He was fined £300 for each offence, which took place between April and June 2012, Westminster City Council said. In addition, the council was awarded costs of £3,919 and a victim surcharge of £15 during yesterday's hearing.

Councillor Audrey Lewis, licensing chairwoman at Westminster City Council, said: "This was a surprising move which, if it had been allowed to succeed, could have paved the way for an end to the current smoking ban.

"We are relieved that the magistrate saw this for what it was and dismissed the defence's argument."

Shisha smoking is a way of smoking tobacco through a bowl and hose or tube. There are an estimated 150 shisha bars in Westminster, a council spokesman said.

Cllr Lewis added: "In recent years we've seen an explosion in the numbers of shisha bars opening up in Westminster.

"This isn't the first prosecution we've had against premises that have allowed shisha to be smoked indoors. In the past we've found people smoking in basements, which is an obvious safety hazard."