The Mayor of London has warned that charging drivers to enter a city centre is not an efficient way of raising money.
The Major of London says charges will cut traffic but may not raise revenue
Ken Livingstone said the main aim of such a scheme should be to improve traffic flows.
Edinburgh has been undertaking a consultation exercise on introducing congestion charges.
It is one year since London started asking drivers to pay for entering the centre of the city.
Two concentric zones are planned for Edinburgh, with a £2 charge applying in the inner zone from 0630 to 1900.
An outer ring, 20 miles in circumference, will only operate between 0700 and 1000.
Following Edinburgh City Council's consultation on the plan, a referendum is expected later this year.
If the plan is approved charging could be introduced in Edinburgh early in 2006.
Cardiff has been looking at a similar approach and the experience of charging in central London has played a part in encouraging cities across Europe to look at similar schemes.
Stockholm has been reported to be planning a pilot project next year, and Barcelona and Milan may follow soon after.
There has, however, been a mixed response to the London scheme in the twelve months of its operation.
The Royal Institute of Chartered Surveyors has said the retail sector is the "big loser".
It published a study this week indicating that 90% of retailers and 75% of leisure occupiers view the charge negatively, and believe turnover is suffering.
But charging has been given the thumbs-up in research carried out by the lobbying group London First.
It found that 72% of companies in London believe the road charging experiment is working, with only 14% convinced it is a failure.
Speaking on the BBC's Newsnight Scotland programme, Mr Livingstone said: "Don't do it for the money.
"I always emphasise this wasn't a tax on motorists; it was about freeing up the city."
Mr Livingstone pointed out that even the most optimistic projection of income from the charges in London, at about £150m, would be a relatively small sum in comparison with the billion pounds which comes from central government for investment in transport in the city.
He also suggested that motorists have to be given viable options for their journeys into the city centre.
He said: "You have to have good public transport alternatives in place.
"None of us anticipated the shift to the bus."
Passenger numbers on buses through central London are reported to by up by 20% in the past year.
Councillor Andrew Burns, the executive member for transport, said the experience of London showed that congestion charges had been an "outstanding" success.
But he said the lower revenues did not raise questions over Edinburgh's plans.
"In Edinburgh we're looking at an inbound cordon-crossing scheme, so you only pay the proposed £2 when you cross into a cordon," said Mr Burns.
"We know exactly how many vehicles come into Edinburgh and where they come form, because it's easy to extract that information from the census data, so our predictions and projections are much more robust than London's ever could have been."