I’ve just spent the last three days pottering around in the new Saab 9-5. This is one big machine, just nudging over five metres from nose to tail. It’s very wide, too.

The six months I spent in the related Vauxhall Insignia were marked by the difficultly of squeezing into a typical parking space and then trying to get out when the door could only be opened by a few inches.

The 9-5 is based on the long-wheelbase version of GM’s Global Epsilon platform (aimed mainly at the legroom-obsessed Chinese market), which makes it hard to fit into the parking spaces lengthways as well as widthways.

Turning into side roads also takes a bit of extra care because the 9-5 is front-drive. Rear-wheel drive makes it easier to shuffle a long car around the city.

There’s no doubt that the sense of space in the 9-5 cockpit is life-enhancing, but this new Saab must also mark the high point for the ever-expanding girth of mainstream cars.

For years we have got used to cars getting bigger with every generation. But there’s good reason to believe that this expansion has reached its zenith.