It's obvious why car makers are keen on double-clutch gearboxes. If you keep it in 'D' it feels more or less like a normal auto, yet has fuel economy and emissions that are far closer to a manual 'box.

What's more they are invariably equipped with steering wheel buttons or paddles for a DIY shift and so can be sold as a 'sporty' option and we can be charged accordingly.

It's this last point that probably explains why the proliferation of new double-clutch systems this year has largely been fitted to high performance cars and it just so happens that I've driven most of them in the past two weeks: the Mitsubishi Evo X, the Nissan GTR, the Porsche 911 PDK and BMW M3.

I've come away with mixed impressions. The Nissan and Porsche systems are brilliant (if ever so slightly anodyne), but the other two just feel half-baked by comparison.

And it was the M3's system that disappointed me the most as its changes were neither as swift nor as smooth as you'd expect or desire. I'm something of a two-pedal fan but I'd have the manual M3 everytime.

No surprise that certain systems are better than others - why should double-clutch boxes be any different from other systems?