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 imprisonment for a term not exceeding 51 weeks or a fine or both.
In relation to an offence committed before the coming into force of section 281(5) of the Criminal Justice Act 2003 (alteration of penalties for certain summary offences: England and Wales), the reference in subsection (1) to 51 weeks is to be read as a reference to 6 months.
For the purposes of this section it does not matter whether free passage along the highway in question has already been temporarily restricted or temporarily prohibited (whether by a constable, a traffic authority or otherwise).
In subsection (1B), "traffic authority" has the same meaning as in the Road Traffic Regulation Act 1984 (see section 121A of that Act).
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