Cabinet ministers are being urged to set an example to drivers everywhere by choosing a cheap and environmentally friendly model of ministerial car.
All members of the Cabinet have been told by the government car pool that when their car is up for renewal they can swap it either for an XL Jaguar or a Toyota Prius.
The Jaguar costs £50,000 and is regarded by environmentalists as a "gas guzzler", although it runs on biodiesel, which contains a 5 per cent blend of vegetable oil. The Toyota - priced at £17,500 - has a "hybrid" engine, running on petrol and electricity, which cuts its carbon emissions.
One Cabinet minister said last night that he will take the expensive option on security grounds.
Tony Bosworth of the environmental group Friends of the Earth said: "Cabinet ministers must lead by example. Transport is responsible for a quarter of carbon emissions. We have got to get those emissions down, and using cleaner cars is a great way to help."
Norman Lamb, the Liberal Democrat industry spokesman, said: "It compromises the Government's clear message on climate change to put ministers on plush leather seats in petrol-guzzling Jaguars."
Previously, the Government Car and Dispatch Agency bought vehicles from Rover to demonstrate its commitment to the British car industry. However, the sale of Rover to Nanjing Automotive, a Chinese car company, last year will bring an end to the sight of ministers being whisked around town in Rover 75s. Another popular ministerial car, the Vauxhall Omega, has gone out of production.