Revellers who leave their drinks will come back to a reminder

Spiking is believed to be behind a series of rapes and sexual assaults across the UK.

Mercy, a club on Prince of Wales Road, began its "Have you been spiked?"' campaign this weekend.

Staff have been dropping cocktail stirrers bearing an awareness label into drinks left unattended to remind clubgoers someone could easily have tampered with them.

Other nightclubs are using "Spike", a green hedgehog which bears a similar message and a helpline number for more information.

The risk is actually about losing control and becoming a victim - spiking is not a new thing Inspector Gavin Tempest Norfolk Police

Maxine Kelf, a counsellor with the Norwich Rape Crisis Hotline, welcomed the awareness drive.

"I think some might know what could happen, but if you have a drink you tend to go out on the dance floor, forget and just pick up your drink," she said.

"If you're enjoying yourself, things can go out of your head; this will remind people to be careful."

Ms Kelf said counsellors at the hotline have dealt with calls from women who suspected they had been drugged before being raped.

Inspector Gavin Tempest said: "There has been a lot of publicity lately about Rohypnol and other so-called "date rape" drugs.

"The risk is actually about losing control and becoming a victim - spiking is not a new thing."

Posters in Norwich nightspots urge clubbers to keep an eye on their drinks, and at Mercy, actor-comedian Richard Blackwood and former EastEnders star Dean Gaffney will make appearances to push awareness in weeks to come.

The drive is part of Operation Enterprise, a project run by Norfolk Constabulary, Norwich City Centre Management Team and Norfolk Drugs and Alcohol Action Team.