Health and Safety at Work Act 1974
Section 20(2): Powers of Inspectors.
In brief, an Inspector may...
(a) Enter premises at any reasonable time (or, where he suspects a dangerous situation, at any time).
(b) Take a constable with him if he feels he might be seriously obstructed.
(c)(i) Take any (authorised) person with him and (ii) any equipment or materials he needs.
(d) Conduct investigations and examinations.
(e) Order premises or parts of them to be left undisturbed for as long as he needs.
(f) Take measurements, photographs and recordings if his investigation requires.
(g) Take samples of articles, substances or the atmosphere if he needs.
(h) Subject any article or substance to test, dismantling or other process if he feels that it caused or could cause danger.
(i) Take possession of the article/substance and examine it, or ensure it is not tampered with or make it available as evidence.
(j) Require any person whom he reasonably believes has information relevant to his investigation or examination to answer such questions as he sees fit; and, require that person to sign a declaration of the truth of his answers.
(k)(i)&(ii) Require the production of any book or document whether required to be kept by law or not.
(l) Require any person to afford him such facilities and assistance as are within that person's control so he may exercise his powers.
(m) Any other power he might need.
Section 20(m) provides for any other power the Inspector may need. Of particular interest, two such powers are...Read More.
Also see sections 108-109 of the Environment Act 1995.