Like many of you, I’ve read Matt Burt’s recent first drive of the all-electric Renault Fluence ZE. The car looks to be a well resolved, refined contemporary saloon, albeit one powered by batteries rather than petrol or diesel, which is all very exciting for the future of motoring.

Now, I should make it clear at this point that I am in no way against electric cars, but I am against paying a penny more for anything than I have to. So when I came across the figures for charging costs and battery leasing at the end of Matt’s report, I decided to do a few sums.

(I should also state at this point that I failed my maths O-level not once but twice, so feel free to rip the following calculations apart and make me look as stupid as my apparent lack of academic ability did 26 years ago.)

Anyway, Matt says that the Fluence ZE can cost “as little as £3 to ‘fill up’”, which I have no reason to doubt. Matt also tells us that the Fluence’s batteries are leased, at a starting cost of £69.90 a month, but that this cost goes up the more mileage you do. In fact, that £69.90 per month is for a minimum-term lease of 36 months, and up to 60 months.

So, that means you’re paying £70 a month plus charging costs. Those 6000 miles a year work out at 115 miles a week. Assuming, let’s say, an average 80-mile range and £3 per charge to fill the batteries, you’re looking at £4.33 a week in charging, or £17 or so a month, totalling £87 a month combined with battery lease costs.