The beauty of it was that Boris, who is of course a former MP for Henley, footed the bill of around £12 because we didn’t have to pay his congestion charge of £11.50 for our day out in London.
The reason was that this week’s drive - the Audi A3 Sportback e-tron, one of the most capable “green” cars I have driven - is congestion charge-free.
Its COÂ² emissions rack up at an extraordinary 35g/km. To give you some idea of how good that is, some of the most powerful 4x4s leave sooty emission footprints of around 195g/km in their wake.
So the A3 Sportback e-tron’s green credentials are impeccable (which also makes it exempt from vehicle excise duty) but what’s it like to drive?
And could you live with it, that is, does it fulfil the crucial requisites of any sane motorist that its electric engine (EV) range in miles does not cause anxiety and is there a conventional engine there as back-up all the time?
Well, yes on both counts. We all I’m sure applaud any progress car manufacturers make in going green but no one wants to run out of power in an EV or plug-in hybrid and be stranded. You need never have this anxiety with the A3 Sportback e-tron.
The e-tron has two engines: a 1,395cc petrol unit and a hybrid drive electric engine (using a lithium-ion battery system).
As far as I can see one complements the other in this system. It is described as a plug-in hybrid but the very nature of this car means that you don’t have to “plug in” that often.
The conventional engine can regenerate power into the battery so the driver can use the car, say around town or city, solely as an EV. Once out on the motorway or major roads the A3 e-tron reverts to its conventional engine, which can produce impressive performance in sport mode.
Of course if you do drive the car sportily then you can expect a much more conventional result with regard to miles-per-gallon: fuel consumption overall for this car in official terms comes out at a staggering 188.3mpg.
I’m sure the more you drove the A3 e-tron the closer you might get to achieving this but make no mistake this car returns mpg to please the grumpiest of grumpy fuel-obsessed motorists.
The e-tron gives the driver the best of all worlds (as well as a modest lunch on Boris Johnson when the urge takes you to spend a day out in London).
The Audi e-tron can be recharged at charging bays in service stations now found everywhere in the UK. Or you can have a dedicated domestic charging point installed at your home. I think if you are going to invest in this kind of vehicle the latter is a must.
Then in the same way you might charge up your mobile phone at home you are also able to top up the car.
• A3 Sportback e-tron from Â£34,950 on-the-road (excluding UK government incentives)
• Electric power makes 176.6mpg and CO
emissions of 37g/km possible
• Combined 204PS of system power and 350Nm of system torque â?? 0 to 62mph in 7.6 seconds, 137mph top speed
• Capable of travelling at up to 80mph for up to 31 miles under purely electric power â?? total range of up to 584 miles
• Specification including LED headlights, HDD navigation and Audi connect internet-based services
• The charge status of the A3 Sportback e-tron can be monitored from a smartphone using the e-tron app or via the e-tron web portal