Sorry to disagree but talking from first hand experience, the police deem that when driving bare foot you don't have proper control. The same applies when driving in wellies.
I would be interested to know the definitive piece of legislation which makes it illegal to drive barefoot in Scotland.
Researching the subject on Go Ogle only brings up various versions of the press release for Sheilas' Wheels 'Safe Shoes' report (as used in the design concept launch for the �Sheila Driving Heel�) which makes the claim without qualifying its source.