TAXI drivers have been ordered off the roads of Kirklees in a crackdown on fake insurance documents.
In series of spot-checks 25 drivers were found to have false documents.
And council officials have pledged to get tougher.
It is believed some of the drivers had bought forged insurance documents for a fraction of the cost of the real thing.
Some drivers may face bills of up to £4,000 for insurance as taxi drivers.
The dodgy documents are thought to have changed hands for a few hundred pounds.
And council officials think an organised gang is behind the forgeries.
Doug Holliday, group licensing officer for Kirklees, said: "Some of these documents are very good.
"There could be some syndicate involved with this. It may well be a nationwide problem."
Clr David Sheard, chairman of Kirklees's Licensing and Safety Committee, said: "The people who have got these certificates know what they are buying.
"You don't buy insurance off someone in a pub or on the street."
Drivers who have been caught said they thought they were buying genuine insurance cheaply.
One man, a driver from Birkby, has appeared before Huddersfield magistrates, charged with offences including driving without insurance.
Khalif Saleem, of George Avenue, who had been working for a Huddersfield taxi firm, was given a 12-month driving ban.
He was also ordered to carry out 320 hours' community service.
A council spokesman said: "Kirklees issues private hire licences with strict conditions, including that the vehicles are insured to carry passengers."
The council has about 1,600 private hire licences in use.
Kirklees Council works with insurance companies to check that all licensed private hire vehicles have valid insurance.