> In the UK I get the impression you can trundle along at any speed

the regulation is that peds must not delay on crossings.

http://www.legislation.gov.uk/uksi/1997/2400/part/I/crosshea...

> 19. No pedestrian shall remain on the carriageway within the limits of a crossing longer than is necessary for that pedestrian to pass over the crossing with reasonable despatch.

(I'm not sure this is latest version)