20.—(1) The functions of the responsible authority under any of regulations 7 to 11 and 13 may be exercised by a person authorised by the responsible authority for the purpose or by employees of such a person.
(2) Anything done or omitted to be done by or in relation to an authorised person (or an employee of that person) in, or in connection with, the exercise or purported exercise of the function concerned is to be treated for all purposes as done or omitted to be done by or in relation to the responsible authority.
(3) But paragraph (2) does not apply for the purposes of—
(a)so much of any contract made between the authorised person and the responsible authority as relates to the exercise of the function, or
(b)any criminal proceedings brought in respect of anything done or omitted to be done by an authorised person (or an employee of that person).
(4) In paragraphs (2) and (3), “authorised person” means a person authorised to exercise any function by virtue of paragraph (1).