I see Tory MPs want to reduce the distance to 1.5 metres, great let's all get our tape measures out to ensure we have only taken the extra 50cm. All that does is let some people take more liberties.
How about the policy just be try and give the maximum space possible, outside on non busy days that could be 8/9 meters, on busier days 3/4m, inside small shops you may be quite close but you have the decision whether or not to go in.
You can just see the I'm alright Jack's pitching their picnic blankets exactly 1.5 meters from someone, or coughing in the back of your head in a queue if those are THE rules.