WE'VE all been there. Driving for hours while the missus snoozes in the front passenger seat.

Then she wakes to say she might as well be talking to herself because you never even acknowledge her presence, let alone engage in conversation.

Well last week was an exception. I decided to let ‘government' wallow in sumptuous luxury, by showing her how to operate the massage function on the Mercedes-Benz S-Class.

For the next couple of hours she basked in the big saloon's Exclusive Passion leather seats while listening to some ambient sounds through the car's 15-speaker surround sound system.

To be fair, it wasn't too bad in the driver's seat either because, not to put too fine a point on it, when it comes to sub-hundred grand luxury motoring the spacious S-Class is as good as it gets.

Pretenders to the crown come and go but the big Benz just stays on top, with more safety gizmos here and improvements in efficiency there.

Totting up the standard kit on this long wheelbase model revealed a staggering 79 different individual items ranging from convenience features like an automatically lowering head restraint to thoughtful touches like  illuminated vanity mirrors for rear passengers.

If you really want to whack up the tab there are the options, 22 of which appeared on the tested 350 L BlueTEC model for a total bill of, wait for it, £30,495.

They included Night View Assist - with infrared reflective windscreen and pedestrian detection - at £1,690, a TV tuner at a princely £855 and topping the tally a Bang & Olufsen front seat entertainment package for a whopping £6,700.

And of course just about everything can be operated via a rotary dial placed between the front seats.

The V6 diesel engine in the 350 L BlueTEC is the most economical in the S-Class range, returning a very acceptable figure of 41.5mpg on the combined cycle. It's also strong, silent and nicely refined.

Need some instant punch and there's a thunderous rush from the 258bhp on tap, otherwise the Benz cruises effortlessly at speed with a nice controlled balance from the steering.

And the car's airMATIC suspension assesses both driving style and road condition to ensure the optimum mix of ride quality and handling.

Safety is paramount in the S-Class with everything from Attention Assist, which can gauge when a weary driver loses concentration, to ESP, skid control, multiple airbags and child seat recognition included in the price.