MP John Healey, customs minister and economic secretary to the Treasury, took delivery of 40 Honda Civic IMA petrol-electric hybrids.
The new models will add to the group's existing alternatively-fuelled fleet of liquefied petroleum gas (LPG), bi-fuel cars and Toyota Prius petrol-electric hybrids.
Healey said: 'Customs has a major role in protecting the environment, operating a range of environmental instruments from the climate change levy to the landfill tax. It is good to see Customs leading the way with the delivery of these 40 environmentally-friendly vehicles.'
The new hybrids will boost the group's current 2,400-strong fleet, which includes specialist vehicles used at ports, airports, as dog vans and as road fuel testing vehicles alongside pool cars for ordinary transport duties.
HM Customs and Excise secured the Fleet News 2004 UK Fleet of the Year award sponsored by Mazda in March this year.