PRESSURE has intensified on Transport for London (TfL) to exempt more 'essential' workers, including company car and van drivers, from the capital's forthcoming congestion charging scheme.

Estimates indicate that the £5 per day per vehicle charge could cost the Post Office £4 million a year for Royal Mail vehicles, while the Metropolitan Police has calculated that the charges will add £1 million a year to its cost base for undercover vehicles because these will not be registered on TfL's exempt vehicle database.

Angie Bray, Conservative congestion charging spokesperson on the Greater London Authority, said: 'Many public sector workers who, by the very nature of their work, have to put in unsociable hours are extremely concerned about the impact of the charge on their pay packets.

'Since motorists will be charged even if they are just leaving the zone, those who start work in the early hours of the morning will be charged for the privilege of driving home, when they had no other viable alternative for their transport needs that day.'

She said the scheme, scheduled for launch next February, would be viewed as a 'crude tax-raising mechanism' until Mayor of London Ken Livingstone deals with exemptions.

The Fire Brigade Union has already said that all firemen in central London will look for alternative stations due to the charge, while only 15% of ambulance drivers live within a five-mile radius of central London leaving them with few options but to drive to work for night shifts.

Bray said this could lead to an exodus of essential workers from the capital at a time when there was already a severe shortage of staff.

However, the Green Party is accusing Livingstone of not doing enough to promote congestion charging and has defended the concept. It claims the scheme will hit motorists from outside London rather than residents, and that it embodies the 'polluter pays principle'.