GREEN fleets anticipating discounts from congestion charges in London because they run alternatively-fuelled vehicles are in danger of falling foul of the small print of the capital's charging scheme.

Originally, companies running gas-powered vehicles claimed a victory when the scheme promised 100% discounts for both mono and bi-fuel vehicles capable of running on liquefied petroleum gas or compressed natural gas.

However, it has now become clear that the discount is not available to all gas-powered vehicles, but only those that meet the most stringent emissions standards. This means the vast majority of alternatively-fuelled vehicles will not qualify for any discount from the £5 per vehicle daily charge.

To qualify for a discount, cars and LCVs converted to LPG must have emissions that represent a 30% improvement on Euro IV emission levels and be on the TransportAction PowerShift register. Powershift grants subsidise the additional cost of converting a vehicle to run on gas, and as a rule of thumb London charging discounts will only be available to vehicles that are eligible for the highest level of Powershift subsidy.

There are 31 new vehicles and aftermarket conversions on the Powershift register that meet the stringent emission standards required to avoid congestion charges, and TransportAction says it has awarded grants to 1,360 cars and vans that meet these standards. However, with an estimated 50,000 gas-powered cars and vans on the road, it is clear that the vast majority will have to pay congestion fees.

A spokesman for Transport for London said: 'Fleets applying for a 100% discount for vehicles running on alternative fuels will have their details cross-checked with the Power- Shift Register. If they are not on the register, then they won't qualify for a discount.'

The warning follows details of how much London mayor Ken Livingstone will be spending on getting the congestion charging scheme up and running. About £200 million will be invested before the launch in February 2003, with a further £230 million over five years.