We promise not to make any jokes involving the words, "lead" or "charge". Urban police are to take delivery of the first eight Nissan Leafs, complete with sirens and blue lights.

The electric Nissans will be used mainly as part of the Safe School Program, called PSP, but they can be called upon to perform other police duties at any time.

The Nissan Leaf was chosen by PSP as part of its push to reduce its ecological footprint. "We pride ourselves in being the first police force in the world to incorporate cars with zero-emission technology as part of our 5,000 vehicle fleet," said Superintendent Paul Gomes Valente, National Director of PSP.

"We want to continue reducing pollution in large urban centres and the introduction of the 100 per cent electric Nissan Leaf sets a new benchmark for our fleet," he added.

We hate to be pedantic (all right, we quite like being pedantic), but the Leaf is not actually zero emission unless all the electricity it runs on is generated from wind, water or solar. In the UK, its CO2 figure is about 80 g/km, so a little better than the best currently available diesel engine. Where it is obviously much better is in improving urban air quality, as the emissions are moved to a power station.