Citroen C3

This C3 is the first ever Citroen to break the magic 100g/km CO2 barrier. Brilliant, excellent, but I can't help thinking they've got their pricing a bit squiffy. Hand me my calculator! Cancelling out the added extras - no easy task - the 99g/km C3 commands a [tap] £950 premium over the standard 1.6-litre, 90bhp diesel C3, which manages 68.9mpg and coughs out 105g/km of CO2 with the same power output.

£950, for a [tap] 5.4mpg and 6g/km improvement. With diesel currently hovering at £1.20 per litre, you'll have to clock up [tap-tap-tap] 170,000 miles in the 99g/km C3 just to recoup your initial outlay. And that's if you achieve the quoted mpg figure, which you won't.

But, aha, you say: you have forgotten the tax advantages. Correct, correct. The 99g/km C3 qualifies for free road tax, saving you £30 over the dirty, dirty 90bhp diesel. That'll buy you back 15,789 of those extra miles every year, so assuming you do 15,000 miles per annum in your C3 it'll still take you [tap-tap] nearly six years to start breaking into profit. By which point diesel will cost a million pounds a gallon and all our sums will be out.

Fine car though the 99g/km C3 is - quick enough, refined, a nice place to be, if a bit anodyne to drive - it pays to do your maths. Take my calculator and fetch aspirin!

Sam Philip

On your drive for: £359pcm
Performance: 0-62mph in 11.5secs, max speed 112mph, 70.6mpg
Tech: 1560cc, 4cyl, FWD, 90bhp, 170lb ft, 1080kg, 99g/km CO2