What should the speed limit be on a motorway?

When the speed limit was introduced all those years ago, it was at a time when there weren't that many cars on the roads and their mechanics and technology was pre-historic by modern standards.

As shown on top gear on Sunday, an ordinary car would need to be doing well over 100mph to stop within the 315 feet as directed by the highway code. That test was slightly flawed in that The Stig knew exactly when he had to hit the brakes rather than it being a sudden emergency.

Having said that, that stopping distance is seriously outdated and I think the the top speed limit should be raised. The French system isn't bad at all as it takes into account the weather conditions. If the weather is fine, the limit is 130kph (81mph) and if the weather is bad then it is dropped to 110kph (68mph). I'd favour similar speed limits in the UK and don;t see any reasonable reason not to raise the limit to at least 80mph (which most people do anyway).

Problem is..all those cars on Top Gear had carbon ceramic brakes. 

Try stopping that quickly in 2001 Ford Fiesta after passing your test 12 months earlier....and being a woman!!

The Stig did it in a vauxhall astra (or something similar). I remember having to slow down very quickly on the M6. The bloke two cars behind me couldn't manage to stop before hitting the car behind me. All I saw was his bonnet flying into the air. Maybe he was driving too close (probably). That's an issue with raising the speed limit though.