Central London's congestion charge sees its first birthday today, but not everyone in the capital will be celebrating.

While Ken Livingstone extols the virtues of his £5 charge for motorists wishing to enter the central London, Conservative mayoral hopeful Steve Norris is planning to scrap the scheme, and businesses are eyeing plans to extend the zone with caution.

Despite fears the scheme would bring chaos to London's streets on the day it was introduced, one year ago, it went off without a hitch, reducing congestion in the zone by 30 per cent and speeding up bus journeys by around seven per cent in the rush hour.

Mr Livingstone praised the scheme this morning, saying it had "exceeded all my hopes".

"This is the only thing I have been associated with in 31 years in public life which turned out better than I hoped it would," the mayor said.

Problems continue at the customer services centre, however, particularly with regard to disputed penalty charge notices (PCNs), issued to drivers who have failed to pay the charge. Transport commissioner Bob Kiley said only last month there was "still much to be done" in alleviating problems at Capita, the scheme's administrator.

Tory mayoral hopeful, Steve Norris, has said he will declare an amnesty on the PCN fines if elected, claiming it would be "pointless" to pursue motorists disputing their fines.

"Congestion charging is currently haemorrhaging money and ruining business. I intend to start with a clean sheet from day one," Mr Norris said.

Some suggested the levy may become a victim of its own success, after it became clear revenue collected would be much lower than predicted, due to the number of motorists put off driving through the zone.

Only £70million of an anticipated £170million was brought in from the scheme - a claim the mayor this morning countered by saying the charge was never intended as a tax raising measure.

Mayor Livingstone has begun a six-month consultation in west London for an extension of the congestion zone to include Kensington, Chelsea and Westminster.

Residents last night met to voice their opposition to the extension, and the London Chamber of Commerce has expressed reservations.

"We oppose any extension of the scheme until the concerns of business have been addressed and plan a detailed study of the charge's effect on the restaurant sector," the chamber said in a statement.

Steve Norris said: "Shops, restaurants and businesses in the zone have been damaged, many to the point of closure - a fact reinforced by the Royal Institute of Chartered Surveyors which showed that 90% of retailers in the zone had been adversely affected."

Mayor Livingstone will today be celebrating the charge's first birthday with a major press conference at City Hall.

He has until the June election to find out whether the rest of London was celebrating with him.