Mentioning that Britons walk less than almost any other Western country except Greece, while the UK cycling rate is 40% below the EU average, Cameron said: "We will be developing plans to bring about a dramatic improvement in the state of public transport in the UK. We recognise the need for radical thinking to provide cleaner, greener transport in our towns and cities."

On private transport, Cameron said: 'The solution is not to stop people owning and using cars, but to transform the cars we drive. I've swapped my government car for a hybrid with substantially lower emissions. It still produces too much carbon, but it's a move in the right direction.

'I want Britain to be at the forefront of international efforts to build a new generation of motor vehicles that are much less environmentally damaging. And today I'm announcing a radical Conservative agenda for green cars. Our goals are ambitious. We want to bring the average carbon emission level from cars down to 100 grammes per kilometre for new cars by 2022, and for all cars on Britain's roads by 2030.'

The Conservative’s policy document on the subject, which can be downloaded in full from www.conservatives.com, shows the party’s policy is neutral concerning the benefits of different vehicle fuel technologies, but takes note of incentive-based, CO2 target-based programmes that have begun to increase the population of hybrid vehicles abroad, including the Pavley Bill in California, under which manufacturers have until the 2009 model-year to produce vehicles that will collectively emit 22% less greenhouse gases than at present by 2012, and 30% less by 2016.

Believing that setting an objective of an average emission level of 100g/km by 2022 for new cars is a 'challenging but realistic' goal, the Conservatives’ intention is to develop a programme that is cost-neutral – that will alter the balance between the cost of owning a traditionally powered, less environmentally friendly vehicle and the equivalent cost of a new-generation vehicle.