A survey conducted by the Royal Institution of Chartered Surveyors finds that nine out of 10 retailers believe the congestion charge has had a negative impact upon trade.

Despite the report Ken Livingstone will this week launch a consultation on plans to double the size of the charging zone.

Meanwhile, as Edinburgh considers plans to follow London's lead, the AA Motoring Trust said that the "dramatic" reductions in traffic seen in the scheme's early weeks had not been maintained.