I used often to use the Hemel Hempstead Magic Roundabout, which is essentially the same as the Swindon one, and it works very well. It used to be six mini-roundabouts - against Swindon's five - but one road was closed to traffic a couple of years ago.

The first magic roundabout I met was at Colchester. They were experimenting, and laid it out with white-painted tyres. I went there every couple of months and every time it was different, until it settled down to the concept later followed in Swindon.

Hemel also had a wonderful twin spiral multi-storey car park - one spiral up, one down, with level links between them across the middle (like the staircases at Chambord).