A written authorisation from the appropriate Minister is required before a person enters and surveys or values land in exercise of the power conferred by section 172 if—
In subsection (1)—
"the appropriate Minister" means—
(a)in the case of land in Wales held by a water or sewerage undertaker, the Welsh Ministers, and
(b)in any other case, the Secretary of State;
"statutory undertaker" means—
(a)any person who is, or who is deemed to be, a statutory undertaker for the purposes of section 16 or 17 of the Acquisition of Land Act 1981 or of any provision of Part 11 of the Town and Country Planning Act 1990, and
(b)any person in relation to whom the electronic communications code is applied by a direction under section 106(3)(a) of the Communications Act 2003.
Where the survey or valuation is to take place in a street, the following sections of the New Roads and Street Works Act 1991 apply to the survey or valuation as if it were street works—
In the application of those sections references to an "undertaker" are to be read as references to the acquiring authority which authorised the survey or valuation.
See section 169(4) of the Water Industry Act 1991 and section 171(4) of the Water Resources Act 1991 for additional procedures in relation to the exercise of the power in section 172 on behalf of a water undertaker, the Environment Agency or the Natural Resources Body for Wales.