There are plenty of large cars on the road and plenty of luxurious ones, but only a handful that can truly be regarded as majestic.
If you want hotel concierges to snap to attention as you glide effortlessly into the likes of the Hilton or Dorchester in Park Lane, London, then a Rolls-Royce or Bentley will fit the bill admirably.
That's great if you have more than £150,000 at your disposal. But for about £80,000, Jaguar's most luxurious model, the XJ, will graciously deliver a Prime Ministerial air of understated opulence.
High performance and sharp handling lie at the heart of Jaguar's design philosophy, but in the XJ the engineers have been told to chill out and focus their attention firmly on comfort. And boy have they succeeded.
With the long wheelbase version tested here, in particular, the emphasis is on making the ride and rear seat comfort as smooth as humanly possible.
The XJ, which is frequently chauffeur driven, happily fulfils the role of a mobile office with rear seat passengers getting fold-out desks and flip-up TV screens, Bluetooth telephone connection and individual leather seats that are both heated and cooled and even fitted with an inbuilt massager.
Rear seat passengers also have the ability to individually control their air conditioning settings and have access to a 1,300 watt digital surround audio system.
And while the folk in the back get quietly on with their work, life in the soft grain, perforated leather driver's seat is equally privileged. As you would expect from a car in this class, it is electrically adjustable, as is the steering column that automatically retracts when you exit the car.
Despite its size, the XJ is surprisingly nimble, manoeuvrable and dynamic. Power on the test car came from a 3.0-litre V6 diesel that combines a meaty 300 horsepower, while still offering the chance of fuel consumption in the mid 40s.
Technology is packed into every corner, offering welcome assistance when squeezing into tight parking spaces, to a helping hand when cruising at speed in the outside lane of a motorway.
Electronic systems range from rear and front parking aids, including all-round cameras, to a park-assist system that will both parallel and bay park and also drive the car out of tight spots.
Other systems include a camera that recognises traffic signs and displays them on the dashboard, to automatic speed limiter, cruise control and traction control.
Safety devices include blind spot monitoring and a traffic detector when reversing, to a system that automatically pops up the bonnet to minimise injuries to a pedestrian.
Jaguar was so confident with the sophistication of the satellite navigation system that it tested it in Mumbai by taking on the traditional Dabbawalla delivery system in a race through the congested city streets – and winning.
Dabbawallas, who operate on a complex relay system involving trains, buses, cycles and foot, are used by many Mumbai workers to take home-cooked food to their places of work in small 'tiffins' or 'dabbas'. Logistics expert Federal Express even sent its employees over to learn from the system.
The appeal of the XJ to overseas buyers is perhaps illustrated by Jaguar opting to put the car through its paces on the 144-mile, $3bn 'Skyroad', the Yaxi Expressway in the mountainous, earthquake-prone Sichuan Province of China.
Needless to say, like the prowl down Park Lane, the XJ passed the test in effortless style.


Auto facts
Model: Jaguar XJ Autobiography LWB 3.0 V6
Price: £79,600
Insurance group: 50
Fuel consumption (Combined): 48mpg
Top speed: 155mph
Length: 525.5cm/206.9in
Width: 190cm/74.8in
Luggage capacity: 16.9 cu ft
Fuel tank capacity: 16.9 gallons/77 litres
CO2 emissions: 155g/km
Warranty: Three years/100,000 miles