He is known throughout the world for catchphrases like "don't mention the war" and "he's from Barcelona".

But the voice of John Cleese, or one very similar, could soon be reminding shoppers to hold on to their handbags or lock their cars.

Sussex Police has launched a Pop Idol-style contest to find comic impersonators who will record messages warning people of street crime.

The winner's voice will be played on a loop from five solar-powered black boxes attached to railings and lamp-posts around Brighton and Hove from July.

The scheme has already proved successful in Bolton where a soundalike of comic Dave Spikey, of Phoenix Nights fame, startles unwitting supermarket shoppers with warning messages.

Paul Knight, a Sussex Police crime reduction officer, said "We feel a recognisable voice will be paid much more attention and get important crime prevention messages across in a light-hearted way." A Sussex Police spokeswoman said they are searching for memorable, comic voices like those of John Cleese, Graham Norton or Steve Coogan.

She said: "It has proved quite effective elsewhere when people suddenly hear this distinctive voice reminding them to shut their car door or zip up their handbag.

"We're looking for a recognisable voice, someone quite well-known and humourous."

Impersonators have until Friday to enter by phoning a competition line and leaving a message no longer than 20 seconds.

At £200 each, Sussex Police hope the machines will be a cheap way to cut crime.

The spokeswoman added: "Of course we will still have patrolling officers and Police Community Support Officers. This is just another method of preventing crime and if we can do that by putting a smile on people's faces that's great."

To enter telephone the Sussex Police competition line on 01273 665863. Lines close at midnight on Friday.