The Mercedes-Benz S-Class has always been a technological showcase, pioneering everything from stability control to parking sensors.
This all-new version is designed to move things on again, by offering a string of innovations, along with improvements in efficiency, comfort and connectivity.
As with rivals such as the Audi A8 and Jaguar XJ, it will be available in both standard and long-wheelbase forms.
However, Mercedes will also add an extra-long model to the line-up next March, while a Pullman limousine variant – that's designed to replace the extinct Maybach brand – will follow in late 2014.
There are three engines at launch: a 3.0-litre V6 diesel (badged S350 Bluetec), a 3.5-litre petrol-electric hybrid (S400) and a 4.7-litre V8 petrol (S500).
These will be joined in the spring by a 2.1-litre diesel-electric hybrid (S300 Bluetec) that emits just 115g/km of CO2, while a S500-based plug-in hybrid with emissions below 75g/km is due later in 2014.
What's the 2013 Mercedes S-Class like to drive?
The S500 is obviously the quickest-accelerating model in the launch line-up, and it emits an aggressive yet civilised V8 growl when you put your foot down.
However, the much cheaper S350 Bluetec also feels effortlessly fast and flexible. Plus it's one of the most refined diesels we've driven.
The same can't be said of the 2.1-litre engine in the S300 Hybrid, because this transmits some vibration into the cabin and sounds a bit grumbly.
Then again, it is a lot quieter than it is in other Mercedes models, and the way the S300 switches between diesel and electric power is mostly smooth.
The petrol hybrid (the S400) is far more refined, but doesn't pull as strongly as the diesel at low revs – you need to get the revs well above 3000rpm before it really starts to surge forward.
Every S-Class is brilliant at shutting out wind noise – even at autobahn speeds. In fact, the only thing that really disturbs the peace is the odd clonk from the suspension.
The S500 we drove was fitted with a new suspension system called Magic Body Control, and while this isn't cheap at £4340, it's worth considering.
It uses a stereo camera mounted at the top of the windscreen to 'read' the road ahead so it can prepare the suspension for imperfections in the surface. Speed bumps, in particular, are dealt with almost as if they aren't there.
Given how effective Magic Body Control is, it's a little disappointing that it's available only on the S500 model, but cars with the standard air suspension still offer a very smooth ride; only badly broken road surfaces provide cause any noticeable jolts.
Turn in to a corner and there's no disguising the fact that the S-Class is still a heavy car, despite the weight savings that have been made compared with the outgoing model.
That said, body roll is pretty well controlled – particularly when the suspension is in Sport mode – and the S-Class is more agile than you'd expect such a big limo to be.
The steering adds to the pleasure of driving the car yourself (rather than employing a chauffeur to do it for you), because it's nicely weighted and has a natural feel.
All versions of the S-Class will be available with a £2300 Driving Assistance Package, which includes a Stop&Go Pilot system that lets the car automatically follow the car in front in traffic jams; it looks after braking, acceleration and steering.
What's the 2013 Mercedes S-Class like inside?
As you'd expect, the cabin is beautifully finished, with high-quality metal detailing, bespoke switchgear and swathes of double-stitched leather.
However, it also feels very modern, because the dashboard is dominated by two widescreen TFT displays; one has the main instruments for the driver, while the other incorporates sat-nav, vehicle settings and infotainment.
As in other Mercedes, you scroll through the various on-screen menus using a rotary dial that's positioned between the front seats. This time, though, the shortcut buttons for individual systems are by the dial, where they're easy to find and use.
The fact that some of the buttons have raised, Braille-like dots also helps you tell them apart, plus the telephone keypad doubles as 12 programmable shortcuts, and the voice control system works well.
Finding a comfortable driving position is easy, too, thanks to an electrically adjustable seat.
Meanwhile, in the rear there's a choice of layouts, including a three-person bench-style seat, and two individual chairs separated by a centre console with aircraft-style fold-out tables and cupholders that can heat and cool drinks.
Those who intend to be driven can even specify a Chauffeur Pack, which allows the front passenger's seat to be moved right out of the way so the person behind can recline their seat (electrically, of course) and bring out a footrest.
Other options include everything from rear entertainment screens and a 24-speaker audio system, to an adjustable fragrance system and heated motors designed to replicate a 'hot stone' massage.
The boot of the new S-Class is easily big enough to swallow multiple sets of golf clubs, although the boot-mounted sub-woofer that's part of the range-topping audio system does reduce the width of the load space a little.
Should I buy one?
Absolutely. The new S-Class is more comfortable, refined and luxurious than all its rivals, yet it's also capable of more than 50mpg if you opt for the S350 Bluetec – our favourite version.
If you're after the best luxury limo money can buy, this is undoubtedly it.
What Car? says…
BMW 7 Series
Specification S350 Bluetec
Engine size 3.0-litre V6 diesel
Torque 457lb ft
0-62mph 6.8 seconds
Top speed 155mph
Fuel economy 51.4mpg
CO2 emissions 146-151g/km
Specification S400 Hybrid L
Engine size 3.5-litre V6 petrol
Torque 273+184lb ft
0-62mph 6.8 seconds
Top speed 155mph
Fuel economy 44.8mpg
CO2 emissions 147-153g/km
Specification S500 L
Engine size 4.7-litre V8 petrol
Torque 516lb ft
0-62mph 4.8 seconds
Top speed 155mph
Fuel economy 31.7mpg
CO2 emissions 207g/km