I wonder how legal that is.
'If a person, without lawful authority or excuse, in any way wilfully obstructs the free passage along a highway he is guilty of an offence and liable to a fine not exceeding [F1 level 3 on the standard scale].'
- Highways Act 1980 http://www.legislation.gov.uk/ukpga/1980/66/part/IX/crosshea...