But it was the city council that introduced roof signage seven or eight years ago. Now we've got to get rid of it. What will they tell us next - to put a banana on our cars?

Shamim Raja

Helen McIellen, a radio operator, said: "It happens all the time. It's a worry because so many pirate cars are around now.

"You worry about these young girls. They go out drinking and just jump into the first car that comes along."

In the latest incident, a 23-year-old woman was sexually assaulted by a man in a "frenzied" attack after getting into what she believed to be a taxi outside a nightclub in Didsbury.

In conjunction with the police, Manchester City Council are trying to introduce a scheme to get all mini cabs in the city painted white over the next five years.

The plan is for the bonnets to be painted with bumble bees, with signs removed from the roofs of the vehicles.

Police warning

But the Manchester Private Hire Operators Association has launched a legal challenge to the move.

Chairman Shamim Raja said drivers believe a public awareness campaign is needed, rather than yet more identification.

"Ours is a 24-hour trade, and the rate of car crime in Manchester is very high, so our identification discs and roof signs do get stolen occasionally. Whole cars are stolen.

"But it was the city council that introduced roof signage seven or eight years ago. Now we've got to get rid of it.

"What will they tell us next - to put a banana on our cars?

"Hackney carriages are supposed to all be black, but you get them in all colours now - pink, yellow, red.

The police have issued warnings to women out drinking in the city centre at night.

Detective Constable Laurence Dixon from Greater Manchester Police said: "Private hire vehicles are not licensed to collect passengers at the road side.

"They are often difficult to distinguish from ordinary cars.

"If a woman has been out, she should either call a taxi to collect her from where she is or, if she wants to hail a taxi, make sure it's a black cab."

Manchester's private hire cab firms will find out later this month if they have to go ahead with the council's proposals.