Government Ministers have snubbed the Rover 75 for a high-tech environmentallyfriendly car from the Toyota stable.
Eight top politicians have taken delivery of the Toyota Prius, marketed as " the world's cleanest family car".
The hybrid car, named European Car of the Year 2005, runs on both a petrol and electric engine.
It is the car of choice for Hollywood A-listers Leonardo DiCaprio and Cameron Diaz as well as Tory leader Michael Howard.
Cabinet Ministers are given the choice between the £17,545 Prius and a more traditional Rover 75 at £16,395, with junior Ministers choosing between the Toyota and a Ford Mondeo.
The Prius now accounts for eight of the 84 cars in the Government fleet. Number 10 also has two for use by officials. The cars have been purchased in an attempt to meet a Cabinet Office target of achieving a year-on-year reduction in CO2 emissions.
The Toyota Hybrid Synergy Drive technology is central to the Prius. The petrol engine and electric motor work in tandem. At low speeds and in traffic jams, the car runs on electricity, slashing fuel costs and emissions.
When the petrol engine is being used at higher speeds, the car automatically recharges itself.
Its environmental credentials mean it is exempt from London's congestion charge.
Environment Minister Elliot Morley is a fan.
"It's excellent," he told The Independent. " When you accelerate, the petrol engine kicks in with the electric battery so you get good acceleration. It's also really quiet. The downside is when you are driving, people can't hear you coming. I almost ran over someone in the House of Lords who didn't know I was there."
Previously Cabinet Ministers were given the choice of the Rover 75 or a Vauxhall Omega.