Scotland Yard has shown interest in prototype cars from Honda that will run on gas stored in bulletproof tanks in the boot.
The Honda FCX is still being developed, but the Met plans to take four of the new cars from a delivery of 70 due to go to the Greater London Authority by 2010.
The cars produce no harmful emissions – just a trickle of water. The move is part of a drive by the Met Police to cut emissions as oil prices soar thanks to volatility in the market caused by conflict in the Middle East.
The force already has 90 cars in its 6,000-strong fleet using a mix of diesel and vegetable oil, and plans to increase that to 128. It has also experimented with battery-powered electric cars and LPG vehicles, but these have been returned to the manufacturers.
A Scotland Yard spokesman said: ‘We have to wait for the specifications to see what we can do with them. They may be used as patrol cars where the traffic flow makes sense.’