PROTON is pushing its bi-fuel models to fleets with an eye on forthcoming congestion charging schemes, believing it can cash in on the 100% discount for the cleanest alternatively-fuelled vehicles in London.

The firm is using LPG AutoCentre Network to do all of its conversions, at a charge of less than £1,000. A spokesman said all work would be done before delivery of the cars to fleets.

The 1.6-litre Impian's emissions put it in the Powershift Register funding band four grading system, qualifying it both for a 60% Government grant towards the cost of the conversion, and for a 100% discount from congestion charges.

The smaller Proton Wira is eligible for a 50% grant, but because Powershift has put it in funding band three, it will not qualify for a London congestion charging discount.