Politicians advocate electric cars
Top figures from both ends of the political spectrum have spoken out in favour of electric vehicles this week, saying consumers need to be encouraged to switch to low carbon cars.
Government is currently considering the grants for those purchasing electric cars, as well as a 'scrappage' scheme which would pay out to those scrapping their old cars in favour of more environmentally efficient models.
Mr Johnson has said he wants to see 100,000 electric vehicles on the streets of London.
Both announcements are slightly vague - details on the government scheme are thin on the ground while Mr Johnson has simply said he wants to see more electric vehicles out there 'as soon as possible' - but both also promise political support for low carbon vehicles.
Reaction to Mr Brown's announcement has been mixed, with the car manufacturers saying that a similar scrappage system in measures in Germany have simply led to people trading up to bigger cars and claiming that the incentive will not encourage many motorists to go electric due to the current lack of choice in the market.
Green energy groups have pointed out that electric vehicles are only as environmentally friendly as their power source.
"This move is only as green as the electricity that charges the batteries," said Gaynor Hartnell the Renwable Energy Association's director of policy.
"It is vital that the electric vehicles push ties in directly with an even greater expansion of renewable electricity at all scales, otherwise we will be building yet more dirty power stations.
"The government will need to bring renewables, the network infrastructure and car industries together to ensure that this happens."
Meanwhile Boris Johnson has said he will work with businesses, boroughs and other public sector organisations to deliver 25,000 charging points in London's workplaces, retail outlets, streets, public car parks and station car parks by 2015 and attempt to alter planning guidance in the capital so that 20% of parking places in new developments should be equipped with charging points.
Mr Johnson said: "The time for simply talking about electric vehicles is over - we need real action on the ground to make the electric vehicle an easy choice for Londoners.
"I am today committing millions to install the infrastructure needed for when, in just a few years time, these vehicles become much more widely available.
"This is an unprecedented package of measures to make London the electric car capital of Europe.
"By taking these steps, we will not only create green collar jobs, but also smooth the way for less polluting transport choices which will improve our air quality, reduce traffic noise and contribute significantly to my carbon emissions reduction target."
The estimated cost of the 25,000 charging points and conversion of the Greater London Authority fleet is £60million - the Mayor has pledged to fund a third of this and is calling for the Government and the private sector to commit the remainder.