They said the charge would be the end of Ken

When the original zone was started doom-mongers were quick to tell anyone who would listen that it wouldn't work and that it would spell political suicide for the Mayor of London.

The government had been too nervous to introduce the charge, leaving Ken Livingstone to put his career on the line.

Despite a few hiccups and grumbles from many, it would seem that the decision to introduce the congestion charge has been vindicated.

Traffic levels within the zone are 20 per cent less than before the introduction of the charge, reducing congestion and pollution levels.

Cycling has become a much more popular commuting option, with a 72 per cent increase over the same period of time.

Given the success of the scheme, it is perhaps not surprising that it has been extended to cover a much larger part of London.

It is also unsurprising that there are again criticisms of the scheme, suggesting that it will damage business and even that it could be counter-productive because of the resident discounting element.

Some critics have argued that because residents of the new area will receive a hefty discount (90 per cent) on the congestion charge, that it will actually generate more traffic, as the incentive for these residents to leave their cars at home will be lost.

Despite these fears, the new zone went live on February 19 and it will be interesting to see what effect the extension of the scheme will have.

While London is a fairly obvious city for congestion charging, with relatively well-developed alternative infrastructure such as buses, underground and overground rail networks and cycle lanes, other cities and towns with less developed alternatives are also considering congestion charges of their own.

Manchester, Glasgow and Bristol are among the provincial cities that are looking at new ways of tackling increasing traffic levels through charging schemes.

Yet despite the success of the London scheme, the only other congestion charge being made anywhere in the UK is in Durham, where cars have to pay a fee to enter the historic city centre.

No doubt this will change in the next few years, but there is still a collective nervousness among authorities to introduce charging schemes, because of the expected political fallout.

Softening the blow of introducing congestion charges elsewhere will no doubt require substantial further investment in public transport links and improvements to cycling and walking routes.

Investment at this level often takes some years to materialise, perhaps explaining why other cities have been slow to follow London.

I would not be surprised if congestion charging is a normal part of our lives in many cities across the UK within 10 years.

Will it solve traffic problems, or will it just be an unfair tax on less advantaged people? Only time will tell.