Looking through the Health & Safety Executive web site, the majority of items to do with footwear are related to shoes/boots having slip-resistant soles rather than any form or foot protection or safety rating. http://www.ezassignmenthelp.co.uk It appears employers can have a policy requiring people to only wear 'sensible' shoes to work (eg. no open toe shoes or sandals / slip-ons that do not have proper heel support etc).