Falling asleep while testing cars is frowned upon in this business. Quite apart from the probably fatal consequences, if a car manufacturer has gone to the trouble of getting you and its new car to the same place, the accepted etiquette is that you have the good grace to remain conscious long enough to experience it.

But you can’t truly experience a Maybach 62 without going to sleep, because it has been specifically designed to make slumber more comfortable than any other car in history. In this case, not conking out would be unprofessional.

But before I do, a quick guide to the world’s most luxurious production car. Maybach is Mercedes-Benz’s new luxury brand and marks the resurrection of a noble German marque that last made cars before the second world war. There are two versions, the 57 and 62, the numbers referring to their overall length, curiously enough, in decimetres. Even the short version is half a metre (20in) longer than Mercedes’ long-wheelbase S-class.

As I write, however, I am in the back of the yet longer £281,780 Maybach 62. Up front sits my chauffeur Alex and, according to the speedometer in the ceiling in front of me, he is whisking us across Germany at a steady 135mph. According to the usual indicators of speed — wind and road roar — we might as well still be in the car park. No other luxury car has ever come near these levels of refinement.

My seat costs more to make than a Smart city car and, in addition to heating, cooling and massaging its occupant, will turn into a bed at the touch of a button. It’s not fully horizontal but it’s more comfortable than most beds — as it should be, given that its ergonomics are based on the seats used in the space shuttle.

Maybach refinements include a refrigerator between the rear seats and remote control televisions behind the front ones, on which you can also watch DVDs, surf the net or send e-mails. There’s a portable humidor, too. Options include a partition that separates you from your staff (£20,000) and a translucent liquid crystal sunroof that becomes instantly transparent when charged with an electrical current (£10,000). As for interior lights, I lost count at 20 — and that’s just in the back.

The Maybach 62 is a car like no other: none is as refined, as comfortable at speed or more capable of removing you from the realities of life on the road. Just 300 will be built each year, accompanied by 700 of the altogether less remarkable and not much cheaper Maybach 57, which is the same car but with a price of £243,780 and half a metre less rear legroom.

While the 62 is a unique proposition, the 57 feels and looks like a slightly bigger, considerably uglier version of the S-class for which you are expected to pay an extra £156,200 over even the flagship S 600. That price, says Maybach, reflects its exclusivity and when you consider a typical Maybach customer is likely to capitalise at around £40m you can see that such sums are unlikely to raise much of a sweat.

For me, however, Maybach life is about being a passenger in the 62. I did drive it but it didn’t take much to tempt me into the back again. Your chauffeur will find it absurdly quick — it has a 550bhp, twin-turbo V12, currently the most powerful production engine in the world — and a little bit cumbersome, as you’d expect from a car weighing the same as two C-class Mercedes.

In fact, it is far from perfect. The ride around town is surprisingly and disappointingly fidgety while the instruments and controls are too reminiscent of the common-as-muck S-class for what is ostensibly a breed apart. Maybe 62 owners will never sit in the front and won’t care but the 57 is aimed at the owner/driver, who won’t thank Maybach for reminding him that he could have bought the same driving environment in an S-class for one-fifth of the money.

Technically, the 57 is the better car. It’s less ugly and rides better. But it feels like only the next step up the ladder from the S-class, and I’m struggling to see how it’s worth it.

But I can see exactly why someone would buy a 62. There are executives in their thousands who need to run their businesses while on the move and be able to rest before, between and after meetings. Those who can afford it will find this Maybach transforms the quality of their working life. To them a 62 will not be an extravagance but an essential business tool.

My only true disappointment is that I still didn’t connect with it at an emotional level. It’s been a long time indeed since I was so impressed by a new car but the heartstrings remained untwanged. Which means BMW has a golden opportunity when it relaunches Rolls-Royce next year.

Vital statistics
Model Maybach 62
Engine type V12, 5513cc, twin-turbocharged
Power 550bhp @ 5250rpm
Torque 664lb ft @ 2300rpm
Gearbox Five-speed automatic
Suspension (front) double wishbones, air springs, anti-roll bar; (rear) multi-link rear axle, air springs, anti-roll bar
Tyres 275/50 WR 19
Top speed 155mph
Acceleration 0 to 60mph: 5.4sec
Fuel 17.7mpg (combined)
CO2 383g/km
Company car tax £39,372 for a higher-rate taxpayer
Price £281,780
Verdict The most luxurious production car in the world but it's not perfect