Waterworks Clauses Act 1952

Before the undertakers open or break up any street, bridge, sewer, drain, or tunnel, they shall give to the persons under whose control or management those things may be, or to their clerk, surveyor, or other officer notice in writing of their intention to open or break them up, not less than seven clear days before beginning the work, except in cases of emergency arising from defects in any of the pipes or other works, and then so soon as is possible after the beginning of the work or the necessity for it has arisen.