17.5p per mile is wildly optimistic with diesel at nearly two quid a litre.

I'm currently paying around 95p/litre for gas, which works out at around 23p per mile, in something with a 4.6 litre V8 that's registered as a low-emission vehicle (so cheaper tax) that mostly gets used to drag heavy trailers about the place.

If I need to use a car it's because I'm unlikely to be doing less than double-digit miles to somewhere with no public transport.

If I pop out to the supermarket for groceries, I wouldn't even think of cycling. It's quicker to walk...