James May on: vegetables

've met soldiers – infantrymen generally – who like nothing more than to be on foot if they’re in a theatre of war when it all kicks off.

Being on foot gives you autonomy. You can find cover in the slightest change in the terrain, you can move quickly, go virtually anywhere and be master of your own fate.

Others prefer to be in a tank or an armoured vehicle. You’re stuck with it, but it’s safer. Or is it? The foot soldier buys agility at the price of vulnerability, because he has only a bit of body armour to protect him. You can shoot at a Mastiff all day long and merely annoy the occupants, but if it’s flipped into a flooded ditch by a roadside bomb, you have the problem of trying to get out before you drown.

This is why the techy branch of the British forces are talking about something called the “survivability onion”. Let’s be clear: there are no actual onions in action at present, except in the cookhouse. Rather, the onion is a device for thinking.

So, on the outside of the onion is an infinitely fast foot soldier, equipped with a sidearm that will lay waste to nations but weighs nothing. At the core of the onion is an invisible armoured car that can withstand a direct hit from weapons not yet invented. Neither of these things is possible, so we’ll have to consider the layers in between. Where do we want to be?

Onion-inspired experimentation in thought is not a new idea. The ancient Greeks perceived of the heavens as being layered like an onion, though again not literally. “Life is like an onion,” said the American poet Carl Sandburg. “You peel it off one layer at a time, and sometimes you weep.” Useful allegorical device, the onion.

Where were we? Oh yes, in the onion. Nearer to the middle, you will be better protected. Nearer the skin, you will be more versatile, which is a form of protection in itself. To put this in the context of the armoured vehicles I drove for the show, the Mastiff is nearer the middle and the Foxhound is further out. You will survive a bigger blast in the Mastiff, but you might avoid it altogether in the goat-like Foxhound. But if you don’t avoid it, it will look a bit NBG because it’s only lightly armoured. If it had more armour it would be more oniony. See?

There are many layers to an onion, and only the theoretical molecular centre and outer edge are perfectly acceptable. Everything else is a compromise of some sort, so the debate will last longer than the flatulence from French onion soup. Let’s move this on.

Can we apply the onion to cars? I hope so, having got this far. I thought there might be a straightforward performance onion, in which, towards the centre, cars become faster around a track, but less wieldy in the real world. But I realised this was a carrot, getting fatter as you move along it.

Then I came up with the performance/cost onion, in which the centre is a very fast and priceless car, and the skin is a free one that still goes. The McLaren P1 is towards the centre, and pretty near the outside is that £750 Fiesta XR2 I nearly died in, a few weeks back.

Actually, the performance/cost onion has been around as long as the car. The Lagonda V12 and an Austin 7 Special have been in the onion all along. But something interesting is happening.

Finally, carmakers, unlike Clarkson, are beginning to understand the real value of losing weight. A couple of cars we’ve had on recently have illustrated this – the Alfa 4C and the Caterham 160. The Alfa loses weight so it can perform well with a modest engine intelligently turbocharged. But it’s still a bit too wide, so it’s too far up the carrot.

The 160 recognises, as the original Lotus did, that simplicity, low power and small tyres move the excitement of driving a Caterham further out from the centre of the onion. That is, cheaper. But still well in the onion, because it’s brilliant. Not ultimately as exciting as a Superlight Caterham, granted, but better than its position in the onion suggests it should be.

Most of us are dimly aware of the onion, and subconsciously crave its rich, dense heart. But the onion itself is changing. It’s elongated at the ends, where the traditional balance between performance and cost is being distorted. 

In fact, it’s now more like the shallot of performance. The pointy ends are the bit we’ve always chopped off and thrown away, but they’re where your next car probably lives.

Next month: the kumquat of comfort.