The Royal Institute of Chartered Surveyors has published a report which shows the mixed fortunes of those affected by the charge through its impacts on property and business.

The retail sector is the big loser. The report shows that 90 per cent of retailers and 75 per cent of leisure occupiers view the charge negatively.

Party Response: Liberal Democrats

Liberal Democrat mayoral candidate Simon Hughes MP said: "It is time for a fresh direction to get congestion charging working for Londoners rather than against them; to improve their lives rather than make them a misery; to encourage shoppers back to London streets and to stop law abiding motorists from being unnecessarily fined by Capita.

"Extending C-charge further will be like trying to run before the zone can walk. Report after report has highlighted problems with the existing system that need to be ironed out before expansion should even begin to be considered. There is clear evidence that an expansion would be costly and not help manage traffic levels in this area of London."

Forum Response: Construction Products Association

Jean Emblin, external affairs director, Construction Products Association told ePolitix.com: "The results of the RICS survey are not surprising as we know the negative impact that the congestion charge is having on our industry.

"We undertook a survey of contractors, and manufacturers and suppliers of construction products last year. The survey showed that an overwhelming 85 per cent of respondents believed that commercial delivery vehicles servicing London's congestion charging zone should be exempt from the charge. 80 per cent of product manufacturers and suppliers have said that the charge has affected the cost of supplying products within the CCZ, a fact noted by 83 per cent of contractors receiving such products, with almost 50 per cent of contractors and suppliers passing the increased cost on to their clients.

"Further results indicated that only 10 per cent of those surveyed believed that the charge should be extended to cover a wider geographical area, whilst 75 per cent did not believe that that the idea should be extended to other cities in the country."

Forum Response: Institute of Directors

James Walsh, parliamentary adviser at the Institute of Directors, told ePolitix.com: "Given that there is simply no room for more roads in London, it is all the more important that the congestion charge is balanced by a radical expansion of public transport. A year on from the introduction of the congestion charge there is growing evidence that the charge is hitting businesses and costing jobs. The mayor needs to respond to this crucial concern. "

Forum Response: British Retail Consortium

Luke Mayhew, chairman of the London Retail Consortium (LRC) said: "The LRC welcomes the RICS Report on the impact of congestion charging on London property. We believe there is a need for further independent and authoritative research into the true impact of the charge - across the whole spectrum of shops in London, small and large, chains or independent retailers. The LRC would oppose any extension of the congestion charging zone or any increase in prices without a longer trial period and a clearer picture of the effect of the charge on our Capital."