BMW 7 Series

It's astonishing to think that 60 per cent of BMW's 730Ld are sold to people who employ a man to do the wheel-twirling for them. Why? Because this car makes much more sense from the front seat, because it rewards a driver more. Nothing illustrates this better than the fact you get a Sport button in the 730Ld - really, you need something labelled float and relax, not Sport Plus.

True, in the grand scheme of things, you're isolated from the world outside, but compared to a Mercedes S-Class a fraction more noise filters in and the car doesn't waft as much. It picks out too many surface imperfections.

The 3.0-litre diesel is the engine of choice here. It doesn't feel underpowered, despite this 7-Series weighing nearly two tonnes, the refinement is acceptable and the fuel economy and emissions figures are impressive. We averaged 34mpg on our test drive.

As you'd expect, there's plenty of legroom (the extra 140mm in the wheelbase helps with that), and you can spec all the gadgets a mobile office would require, including fully-electric and adjustable rear seats. The aircraft-stlye headrests are particularly good - the sides can be bent round so those in the back don't get a cricked neck if they fall asleep.

Ultimately though, the problem with this car is that it's too sporty. You want to drive it fast. In which case, it's not a very convincing limousine.

Piers Ward