An estimated 600 London taxis have been taken off the roads for safety checks.
It follows a series of sudden engine fires in 12 TX4-specification taxis over the past three months.
Transport for London has suspended the licences of all the cabs that may potentially carry a fault. Only models registered between September 2006 and March 2007 could be affected.
The TX4 is built in Coventry by London Taxi International (LTI).
There are around 21,500 taxis operating in London.