Anybody old enough to remember those Nuclear-Free zones of the 1980s? Looney left local councils declared a small area of a city as a ‘nuclear-free zone’, to demonstrate their right-on credentials.

Lots of people scoffed. Would the Soviet Union, if it decided to nuke the UK, carefully avoid flattening its fellow communists? Would radiation fallout not drift across into the most ideologically-sound streets?

Well, the Nuclear-Free zone is back, but this time it’s called the London Congestion Charge.

Today, Mayor Ken Livingstone announced what has been threatened for the last two years. That cars in Band G (that’s emissions of 225g/km and above) would be charged £25 per day to move in the zone. And if you live in the zone, the 90 percent residents discount will be dropped, too.

Still, if you have a car in the A and B bands, entrance will now be free, instead of £8. There again, if too many of us buy these cars –such as Mini Cooper diesels - Band B will likely be charged at £4 per day from 2010.

The new regime comes in on 27 October and Red Ken says: "The CO2 emissions from the most high powered 4x4s and sports cars can be up to four times as great of those of the least polluting cars. The CO2 charge will encourage people to switch to cleaner vehicles or public transport and ensure that those who choose to carry on driving the most polluting vehicles help pay for the environmental damage they cause."