By Nick Tarry BBC News

But they soon may find their smiles fading because many quite ordinary cars will also fail the new rules on emissions.

Prepare to stone me in the street, but I drive a 4x4. I also live in London.

But I will be sailing through the zone with a broad grin because my Suzuki Vitara has an engine of just 1.6 litres in size and was registered before 2001.

Some really surprising cars will be caught by the �25 charge Dan Stevens, Autocar

My neighbour, however, has a very ordinary-looking Volkswagen Passat. This is not a Chelsea Tractor, nor the kind of car which attracts stickers from activists.

But she will end up paying the �25 per day charge because her vehicle emits 233 grams of CO2 per kilometre driven.

"Some really surprising cars will be caught by the �25 charge," Autocar's news editor Dan Stevens said.

"A 2.0-litre petrol Vauxhall Zafira - a family MPV - emits 228g/km of CO2 and will have to pay.

"And there are plenty of 4x4s and sports cars that will pay the minimum charge of �8."

The number of other ordinary cars which will have to pay the new charge is too long to list, but it includes family favourites such as the Vauxhall Vectra Estate 2.8i V6, several models of the Vauxhall Zafira, Honda Accord 2.4, Volvo V70 2.5T Auto, Peugeot 407 2.7 litre V6, VW Passat 3.2 estate and even the Golf 3.2 (both the three-door and five-door models).

The new �25 charge is not restricted to 4x4s and luxury vehicles

Transport for London has set the level above which you will pay the new �25 charge at 225g of carbon dioxide per kilometre.

Cars registered before March 2001 will pay the charge if their engines are bigger than three litres. Other drivers will pay the regular �8 charge to drive in the London congestion zone.

Interestingly, that includes drivers of the Porsche Boxster 2.7, Jaguar XF V6D and two models of BMW, the 335d and the large four-wheel drive X5 3.0d.

They will not pay the �25 charge, because they are sufficiently technologically advanced to pass under the 225g/km threshold.

The pressure is now on motor manufacturers to lower the carbon dioxide emissions of their popular family cars, which is likely to take a few years. After that, industry experts say, expect the threshold of 225g/km to go down rather than up.

Cars and carbon emissions

Read a selection of your comments:

I fully agree with making those who pollute pay more, just get off the backs of those of us who own & drive 4x4s that are less polluting and take up no more road space than 'family' cars.
Brian Rochester, Tyne and Wear

I drive a car that is nine years old which will undoubtedly fall foul of the new emissions requirements. I do have the occasional need to drive into London and will have to pay �25. The car cost me �3000 two years ago - I'm hardly a fat cat driving a 4x4.
Peter McPhail-Brown, Kent

Are you seriously calling cars like Vectra Estate 2.8i V6, Honda Accord 2.4, Volvo V70 2.5T Auto and the Golf 3.2 - "ordinary cars" and "family favourites"?! These have double-sized engines, and are in the luxury group of models. This is simply about CO2 emissions. It's not a lifestyle/culture war, as some unfortunate victims with big engines feel it to be.
Howard, London

With an increasing desire to cut emissions it is inevitable that the worst vehicles are targeted. 4x4s are designed to be either utility vehicles or executive cruisers, and almost all are oversize, inefficient and wasteful. The real answer is to improve public transport and get people out of cars and onto bikes, trams, buses and trains.
Martin, Aylesbury

I drive a 20 year old Land Rover 110 V8. It is a 4x4, but it is not a "Chelsea Tractor". However, because of the pre-2000 3000cc+ rules, I would be liable for �25 a day. If I want to go to London, or anywhere within, I take a TRAIN.
Iain Sibley, Crawley

All the cars you mention with the exception of the Zafira have well over a 2 litre engine. Anything over 2 litres is unnecessary, even for regular long distance motorway driving.
Charles, Leeds, uk

Sweden is already highly regulated when it comes to vehicle emissions but even we would pay �25 a day. You could do a lot to reduce London's carbon emissions by turning out every other street light at night. London is so bright at night we can almost see it from Sweden!
Philip Celander, Malmo, Sweden

I bought within the congestion zone before it was introduced and then had the congestion charge imposed upon me. I either have to pay, albeit at a reduced rate, or use an overburdened public transport system. I will now feel obliged to sell my car (it has a big engine) by October this year if I want to avoid paying an exorbitant tax imposed upon people wanting to live within the ever expanding zone.
Michael, London, England

I'm happy to pay more tax for driving my 4x4, happy in the knowledge that my extra taxes are be spent on carbon negative initiatives which are going to save the planet.
Steve Bonham, chesterfield

I used to have a fast car but climate change isn't going away. I think this is totally justified. Gas guzzlers really should be banned. If we invest in more cycle lanes this will be the way forward, just give people the infrastructure and you'll be amazed by the number wanting to cycle.
Adrian Bewsey, Wandsworth

I have a Mercedes E320CDI registered in 2000.It emits 270g/km yet I am supposed to pay �25 because of its age and engine size. This is completely unfair and defies any sort of logic.
Ian Greenham, Lambourn, Berkshire