Government ministers have been criticised for not practicing what they preach after it was found that one-third of ministerial vehicles are among some of the highest polluting cars on the road.

Currently, 30 of the 85 cars assigned to ministers and permanent secretaries sit in VED Band F, which is the second most polluting band for cars that emit up to 225g/km of CO2.

A report by the Sustainable Development Commission (SDC) revealed that initiatives to cut the carbon emissions from departmental car fleet are failing.

It found that CO2 emissions from Government cars have actually got worse rather than better.

Carbon emissions from vehicles run by Government departments increased by 1.5% when compared to 2005/6.

“This shows no progress towards achieving the target of a 15% reduction by 2010/11 and is an area of serious concern,” said the commission.

In response, the Government is to create a new ‘centre of expertise’ to help Whitehall departments achieve their targets for reducing carbon emissions.

The Government has also promised that from summer, all new vehicles used by ministers and permanent secretaries - except a small number exempt for operational reasons - will have CO2 emissions below 130g/km.

"Government as a whole needs to take radical action to put its own house in order if it is to be in a position to lead by example,” said SDC spokesman Rebecca Willis.

Stuart Walker, director of public sector fleet specialists Automotive Leasing, added: “This report shows that government and the public sector in general has a long road to travel…The silver lining is that many individual departments have gone a long way towards hitting their targets.

"The challenge now is to make sure that effort spreads to all departments and all organisations.”