If a person—
lights a fire on any land not forming part of a highway which consists of or comprises a carriageway; or
directs or permits a fire to be lit on any such land,
and in consequence a user of any highway which consists of or comprises a carriageway is injured, interrupted or endangered by, or by smoke from, that fire or any other fire caused by that fire, that person is guilty of an offence and liable to a fine not exceeding level 5 on the standard scale.
In any proceedings for an offence under this section it shall be a defence for the accused to prove—
that at the time the fire was lit he was satisfied on reasonable grounds that it was unlikely that users of any highway consisting of or comprising a carriageway would be injured, interrupted or endangered by, or by smoke from, that fire or any other fire caused by that fire; and
either—
that both before and after the fire was lit he did all he reasonably could to prevent users of any such highway from being so injured, interrupted or endangered, or
that he had a reasonable excuse for not doing so.