During the escalation of the Cuban missile crisis, America formed an estimate of the number of troops that Khrushchev had deployed in its “backyard” by tracking the passage of military ships across the water and doing a sum based on the area of those ships' decks. Thus did American intelligence arrive at a figure of around 6,000 to 8,000 troops. What America didn't reckon with was exactly how many soldiers the Soviet Union was prepared to cram into a ship. In fact, Moscow had installed more than 40,000 troops.

The new Peugeot 308 SW works on pretty much the same principle. This is an expanded version of the extremely likeable, chunky-faced 308 hatchback. Even with its extruded back end, its dimensions are relatively humble - almost apologetic. Yet, incredibly, if you go for the option of a pair of tug-up chairs in the boot, it seats seven. Thus you could be driving around with enormous numbers of people inside your 308 SW and the Pentagon would never know.

It would, though (as it did for Khrushchev), depend how many people you were prepared to put in your car and whether you were prepared to surprise others with the unsentimental nature of your feelings in this area. Certainly it should be made clear that the third row of seats in the 308 SW is strictly a small person zone. Children much over ten will struggle to make it through to the back, and won't make themselves comfortable when they get there unless they're prepared to hang parts of themselves out of the conveniently opening window hatch on the back door.

Meanwhile, there is no doubt that you can get three adults across the evenly spaced bench seat in the middle compartment. But they had probably better be familiar with one another to the point of marriage, or, at least, happy to become familiar with one another to that extent.

Apparently it took some of the Russian soldiers two weeks to recover from the gruelling conditions on their voyage to Cuba. I'm not saying that the same would be true for the 308 SW, which does, after all, have air-conditioning, some cup holders and a surprisingly punchy stereo, - but it might be something to bear in mind before you stuff it to capacity and set off for a holiday in Scotland.

Still, it's clear that we're looking at a new development in the gathering trend towards automotive downsizing - the secret estate car. Away with conspicuous bulk: bring on the car that's both a people-carrier and a dump-ready load-lugger but isn't interested in shouting about it.

It's an engaging notion, especially if the car is going to be built as solidly and drive as firmly as this Peugeot. There's a logical flaw, though, because once you have finished filling your 308 SW with children, you have no room left over for the things that tend to come with them, such as baggage, animals, additional wheeled vehicles, etc. It's possible that a communist-era Russian expert in military logistics could come up with something, but it defeated me. Those last two seats fill the boot unless you stow them away and all that's left between them and the back door is a tall, thin space, guarded by a vertically mounted cargo net.

Still, in fairness, this area has its uses. Just say, for argument's sake, that you use your 308 SW in peace time, to collect your daughter from nursery school. And just say she happens to have spent the afternoon making a jelly. And say she now thrusts this jelly upon you for safe transport, the jelly being of a considerable mass, red, and seemingly involving an additional tinned fruit element, the whole construction being contained fairly loosely on a paper plate. What are you going to do?

Well, conveniently enough, I can tell you what you're going to do. You're going to suspend the plated jelly, cunningly, between the cargo net and the rear seat-backs, where the slight elastication of the net will hold the paper plate firmly, but not too firmly, for the duration of your journey. (On a horizontal plane, this is. A vertical plane is no good to you, not unless the jelly is unusually and, indeed, inedibly, well-set. Trust me. I've done this.) So let no one claim that the 308 SW's boot space, in seven-seat mode, is entirely hopeless. For those unforeseen dessert transport moments, it's nigh on unimpeachable.

Mind you, my point about the restricted space still stands, because when you've put the jelly in the boot, as described, there isn't room for anything else, not even another jelly. But then, who ever goes home from nursery with two jellies? Apart, maybe, from someone with two nursery-age children. But that's their problem.

Top speed: 125mph

Acceleration: 0-62 in 11.1 seconds

Average consumption: 47.8mpg

CO2 emissions: 155g/km (amber)

One careful owner: Mother Hubbard

On the stereo: The Partridge Family

In the glovebox: five bags of shopping

Bound for: Staines

Buy it because: your children have friends Marks out of 10: 6

Price: £18,645