Can I thank John Griffiths for giving me a minute in this debate? What's the difference between 20 mph and 30 mph? It doesn't sound very much, does it? Well, the perception, the corner vision, how much you actually see, increases the slower you're going. Your reaction time—. For those who did their driving test many years ago, the back page of 'The Highway Code' told you how long it would take to stop at different speeds. And the faster you're going, the longer your reaction time and the longer it takes you to stop when you actually do react. And the crash outcomes—the faster you're going, the more likely you are to seriously damage what are often little people.

I'll just very briefly recount an article that was in the South Wales Evening Post on Saturday, where Robyn Lee, the columnist, wrote about seeing an accident involving a child who just ran straight into the road and was hit by a car. It wasn't a serious accident; the child was just bruised. Why? Not because it was 20 mph, but because, fortunately, there was a very long traffic jam. We can't rely on traffic jams to keep our children safe; we need 20-mph zones.