The nice old CAA have got around to telling us commercial pilots in a FODCOM - not sure how private pilots are supposed to know about it:
www.caa.co.uk/docs/33/FOD200328.pdf
The abbreviated title of the pdf file may prove significant!
A randomly selected sample of plods on the ground know about as much as we do at the moment. When pressed, they seem to consider it "the same as driving" but with limits at around 15% of the driving limit.
May I wish all of you due to fly early in the New Year in the UK a fairly abstemious holiday!