Toilet backs are being removed in many bars to stop drug users

The advice follows the admission of a Swindon bar owner who uses the same method to prevent drug use.

Graham Prease from Avon and Somerset Police told the BBC that when the drug comes in contact with the WD40 it becomes unusable.

"It congeals into a mess, it then semi-dissolves it and prevents it being sniffed," he said.

"The advice we give for cocaine is to spray level surfaces with WD40 which prevents them from snorting it off these surfaces," he added.

Widely used

"Licensees have been telling me they have had very positive effect with it, because you cannot see the WD40, so the drug user puts the cocaine on it and cannot use it.

"Word soon spreads around and it aids prevention."

Monica Walker from Bar Excellence in Bristol said the drug was widely used by revellers.

"Normally people don't notice it's there until too late, so it ruins their little supply of cocaine.

"In my experience I've caught one person trying to take it off the bar on a busy Friday night, and another person trying to use it on a table.

"It's a much-accepted drug by our customers but it's obviously illegal."