Generally up to 1/4 inch with drifts to 1/2 inch.
I live 25 miles from LHR & 200 m higher up.
I survived the great blizzard of 2017 & would like to thank BA for cancelling my flight from Frankfurt so I had to spend 1 hr on my mobile from Germany scheduling a return early Thursday having arrived noon Wed.
The fact I cancelled many meetings is softened by the knowledge I travelled safely.
BA have just made the UK a laughing stock.