Mind the map: London Underground turns 150

London Underground's iconic map is being celebrated, as part of the service's 150th anniversary.

Designed by Harry Beck in 1931, it abandoned geographical accuracy in favour of simplicity and has become one of Britain's best known designs. It was accepted for use in 1933 and has become the template for underground maps around the world.

But some critics argue that the map has become too busy and that it is time to change it.

Graham Satchell reports