…It’s legal to when cycling, but only if it’s a shared pavement or there is a cycle lane on it. If there is (you’ll know by the blue cycle sign), you can ride on it but you must ride considerately. It makes sense for all users of shared pathways to behave politely!

Highway Code, Rules for Cyclists: 62 When using segregated tracks you MUST keep to the side intended for cyclists as the pedestrian side remains a pavement or footpath. Take care when passing pedestrians, especially children, older or disabled people, and allow them plenty of room. Always be prepared to slow down and stop if necessary.