It seems only right to begin with a confession. It wasn't through an overriding desire to save the planet that I bought my LPG-converted Vauxhall Astra two years ago, but because it would allow me to dodge the London congestion charge, at that time threatening to expand into the area where I work.
I decided to lease rather than buy, and this one came second hand from the civil service. Only days after it was delivered to my door and my Renault Clio driven away as part exchange, some of my friends were referring to me as 'the minister'.
The Astra is spacious and reassuringly solid to drive, with the power steering making parking less of a sweat than other cars I've driven. I still broke a rear light recently by reversing into my neighbour's skip, but fortunately, insurance is competitive and replacement parts are reasonably priced.
LPG (liquid petroleum gas) is a fossil fuel. However, according to the Energy Saving Trust, LPG emits 10-15 per cent less CO2 than petrol and 80 per cent less nitrous oxide than diesel, as well as a fraction of the carbon monoxide. And, with none of the additives of conventional fuels, LPG engines give off no particulate emissions whatsoever.
It's also far better for my wallet, costing me about a third less to run than my previous petrol car.
Vehicle excise duty is also marginally reduced, and it cost me only £10 to register for full congestion charge exemption, so, each time I venture into the controlled zone, I've a smile on my face and an extra £8 in my pocket.
Refuelling, once mastered, is actually easier than petrol: with the hose attached, it's simply a matter of pressing a button. There's no trying to fill to the brim to round off to the nearest pound, no dripping on to your shoes as you finish, just a satisfying belch of released pressure as it's detached. At 50 litres, the LPG tank has a capacity only two litres less than the petrol tank, so on long journeys, I stop to refuel myself more often than my car.
The car can still run on petrol - it is needed to start the engine. One major disadvantage, though, is that, because this is a converted vehicle, the LPG tank had to be fitted into the spare wheel well beneath the boot.
As a result, the spare wheel itself now sits in the boot, vastly reducing the space available, especially alongside a bulky doctor's bag. The LPG tank requires certification every six years, but is checked annually as part of the normal maintenance, adding around £50 to the service cost.
Although recent models may be better, there is a slight loss of performance when running on LPG. On the motorways, it still manages to exceed the speed limit all too comfortably but, in comparison to petrol, LPG is jerkier, requiring more revving to get going. So although it's quieter than petrol, it does cause passers-by to leap for cover as I move away from pedestrian crossings.
I originally chose an LPG car for economic reasons. But it's not just cost-cutting that prompted the prime minister and the Queen (whose four-car LPG fleet includes two Rolls Royces) to convert.
When my lease expires, I'll be swapping the Astra for one of the wide range of LPG conversions available. There's absolutely no reason not to.
- Dr Kelion is a GP in west London
VAUXHALL ASTRA COMFORT Z16XE
Engine: 1.6i 16-valve
MPG: LPG urban 22/ex-urban 38
MPG: Petrol urban 28/ex-urban 49
Costs: Converting a standard petrol car into a dual-fuel can cost between £1,200 and £2,700, while buying a purpose-built dual-fuel adds between £1,500 and £2,000 to the list price.
For a list of LPG refuelling outlets, car converter dealers, plus some converted cars for sale, go to www.autogas.co.uk, www.boostlpg.co.uk.