The checks are similar to ones carried out on scuba diving tanks to check for leaks and ensure there is no corrosion in the tank. According to Jonathan Murray, manager of Powershift, fleets have nothing to fear. He said: 'It is the same with any pressure vessel container of this type. They need checking, normally every three years and approved by a qualified inspector. There are not that many in garages, although there is no reason why not, as staff can easily be trained in their use.'
Ken Dodds, finance and administration manager for the Groundwork Trust, and who runs a fleet of 10 vehicles, five of them - two Escort cars and three Escort vans - running on compressed natural gas, said: 'I have been running these vehicles for five years and they have to be checked every three years. I have had to have one tank replaced so far and it cost £88. Fleets which take on gas should already be aware of it because a certificate of approval for the gas tank should be received with the vehicle.'