21.—(1) Any person who carries out work in relation to a relevant project in contravention of a requirement to discontinue that work in an enforcement notice served on him in accordance with regulation 19 shall be guilty of an offence and liable—
(a)on summary conviction to a fine not exceeding the statutory maximum; or
(b)on conviction on indictment to a fine.
(2) Any person on whom an enforcement notice has been served in accordance with regulation 19 who fails, within the period specified in the enforcement notice, to carry out any measure, other than discontinuance of the relevant project, required by the enforcement notice shall be guilty of an offence and liable on summary conviction to a fine not exceeding the statutory maximum.