Believe it or not this mean machine is a family estate. Sometimes.

Other times it is a 170 mph supercar that would blow kids’ minds on the school run.

But is this the last we will see of the monstrous twin turbo V8 with its colossal horsepower and torque?

There will be a new A6 but with Audi throwing everything at hybrid and electric we shall have to wait and see what form the next RS 6 model will take, if we see one at all.

The Government has, predictably, changed its mind on the deadline for killing off the combustion engine, and even though Audi has started the clear out by dropping the TT the demise of the RS 6 is said to be ‘not imminent’.

For now RS 6 is very much alive and kicking and had an upgrade this year making it even more powerful.

This is the Performance version beefed up to give more horsepower. The bi turbo unit is bigger, increasing boost pressure, while new alloys are 20 kg lighter. These are the sort of lengths you take to make your car faster than the opposition.

The Performance has a self locking differential which ensures max power to all four wheels so there is no scrabbling for grip when the accelerator is stamped to the metal.

All these elements have shaved nearly half a second off the sprint to sixty. For the record that takes just over three seconds and I imagine another four or five seconds would see you crashing through the 120 mph barrier.

Sounds manic, which it is, but we have to accept that this car is too fast for our speed limits. The car is a hooligan and would be locked up if it was human!

Just pressing the start button warns of trouble ahead if you are not careful. It has a glorious roar to get the driver in the mood and can leave you spellbound with just one blip of the accelerator. Floor it and you are hurled back into the seat.

Top speed it governed to 174 mph but I’m pretty certain there is another 20 mph under the bonnet with the limiter disengaged. The 850Nm of torque is whopping so no worries about overtaking.

RS 6 has been revered as the world’s fastest estate car, whether it is better than rival offerings from Mercedes-Benz and BMW can only be decided on a track. On public roads the Audi feels immovable, hardly surprising when it is being pushed to a fraction of its limits.

To put it another way, a driver would have to be stupidly reckless to lose control such is the incredible grip from the quattro drivetrain. Apart from that the RS is stacked to the gunnels with driver safety aids and it is not at all intimidating to drive.

The adaptive cruise control is impressive and came into its own on a drenched motorway where the lack of visibility was scary. Once set the car takes over braking and accelerating from a chosen distance to the vehicle in front. Using traffic sign recognition it automatically slows the car to a lower speed. A new one for me.

As a family estate the RS Avant is sensible, to a point. It easily accommodates five adults with a boot big enough to carry a sizeable piece of furniture with the seats down, or a pile of luggage with the back seats in place.

In reality an A6 Avant is more realistic as family transport given the £127,000 for the RS Performance, and the costs that go with it. Insurance will be sky high, you need to cough up big bucks for the first year road tax and then there is the little matter of low twenties economy, although I did manage 25mpg over nearly 700 miles. Good job the car has a 73 litre tank.

And you might as well go the whole hog with ceramic brakes. An extra £9,200, you would get a good used car for that money, but my goodness they are immense.

I have been saying for 20 years that none of the other premium brands can trim a car like Audi and nothing has changed. This car is beautifully finished although some of the technology is becoming dated and will probably be refreshed in the new model.

Fast Facts

RS 6 Avant Performance

£126,970 (£140,000 tested)

4 litre V8, 8sp tiptronic; 618bhp

0-62mph 3.4secs; 174mph

22.4mpg combined

285g/km. First tax £2,365

Boot: 565-1680 litres

Insurance group 50