It is testament to Audi's remarkable Variable Servicing programme that our A4 2.5 TDI is still not due for a service, despite the odometer now reading well over 20,000 miles.

What's more there seems little actual requirement for a service as nothing has failed or broken in those 20,000 miles, and reliability has been exemplary. I haven't even had to add any oil in that distance. Impressive stuff.

According to the trip computer, there's still another 2,000 miles or so to go before I need lift the phone to book it in, and that, by my reckoning gives a service interval of at least 22,000 miles.

Now that, in anyone's book, is conducive to cost-effective motoring, and helps CAP Monitor post a pence per mile figure for the Audi of just 36.1p/mile over three years/60,000 miles — a figure that compares with 40.3p/mile for the petrol-powered A4 3.0-litre quattro Sport. That may not sound much on its own but it adds up to a cash saving of £2,520 over three years.

The recent spell of cold weather, including a fair amount of snow in our area, has had me relishing the advantages of quattro four-wheel drive.

Sure-footed cornering, no wheelspin on moving off and a general feeling of stability that is absent on most two-wheel drive cars makes the reasons for choosing quattro blindingly obvious.

The attraction of a deserted snowed-over car park was more than I could resist, and I spent a highly entertaining hour or so exploring the Audi's handling limits — with and without ESP, the clever electronic stability programme that, I am convinced, is one of the greatest life-savers on an icy road. A touch too much throttle into a corner and you can feel ESP gently applying the brakes and cutting the gas to bring the car back into line.

Switching the ESP off on my icy car park revealed a less controlled drive and proof, if any were needed that in an emergency ESP could well save your life. Trust Audi to fit it as standard.