Congestion free automatics

Q: I commute into Central London every day (a 70-mile round trip), and want something that's exempt from the Congestion Charge. It also must have an automatic gearbox. I've done some research, but can't find any autos that emit less than 120g/km apart from the Toyota Prius, which I don't fancy. Please help!
Des McSweeney, via email

A: Before you buy anything, you need to be sure it's exempt from the Congestion Charge. Just because a car emits less than 120g/km doesnt mean you'll avoid the fee.

Before Boris Johnson was elected Mayor of London, Ken Livingstone planned to change the Congestion Charge criteria so that all sub-120g/km cars would be exempt, but Johnson scrapped this idea as soon as he came to power.

That means, for the foreseeable future, only hybrids and certain alternative-fuel vehicles avoid paying the charge. A hybrid will probably be your best bet log on to actonco2.direct.gov.uk for a list of suitable cars. You can search for the lowest CO2-emitters in each class, and split the results by the type of car, gearbox (auto or manual) and fuel type.

If you're not keen on the Prius, the only other new option under 35,000 is the new Honda Insight, which starts at 15,490. If you've got big bucks to spend, the Lexus GS 450h, LS 600h or the new RX 450h also avoid the Charge.

We mentioned alternative-fuel vehicles earlier, and LPG-converted cars come under this heading. You could buy one new Subaru offers LPG versions of its 2.0-litre petrol Forester and Legacy (and Legacy 2.5) with an automatic gearbox or buy a car that suits your needs and have it converted retrospectively.

To be eligible for the Congestion Charge exemption, you will have to register with Transport for London (10 a year), but beware even LPG-converted vehicles must meet strict criteria. They must have oxides of nitrogen and hydrocarbon emissions that are at least 40% lower than Euro IV standards, and the company that converted your vehicle must be listed on the TransportEnergy Powershift Register.

To see if your vehicle or converter is on the register, check out www.powershift.org.uk.