21.—(1) Save as otherwise agreed pursuant to article 21(14), subject to the following provisions of this article, the undertaker may at its own expense carry out remedial works to any land, building, apparatus or equipment which may be affected by the authorised project (whether or not within the Order limits), as the undertaker considers necessary or expedient.
(2) Remedial works may be carried out further to paragraph (1)—
(a)at any time before or during the carrying out in the vicinity of the land or building of any part of the authorised project; or
(b)after the completion of that part of the authorised project in the vicinity of the land or building at any time up to the end of the period of 5 years beginning with the day on which that part of the authorised project first comes into use.
(3) For the purpose of determining how the functions under this article are to be exercised the undertaker may enter and survey—
(a)any land or building falling within paragraph (1) and any land within the Order limits; and
(b)where reasonably necessary any land which is adjacent to the land or building but outside the Order limits.
(4) For the purpose of carrying out remedial works under this article to land or a building the undertaker may (subject to paragraphs (5) and (6))—
(a)enter the land or building and any land within the Order limits; and
(b)where the works cannot be carried out reasonably conveniently without entering land which is adjacent to the land or building but outside the Order limits, enter the adjacent land (but not any building erected on it).
(5) Before exercising—
(a)a right under paragraph (1) to carry out remedial works to land or a building;
(b)a right under paragraph (3)(a) to enter land or a building and land within the Order limits;
(c)a right under paragraph 3(b) to enter land;
(d)a right under paragraph (4)(a) to enter land or a building and land within the Order limits; or
(e)a right under paragraph (4)(b) to enter land,
the undertaker shall, except in the case of emergency, serve on the owners and occupiers of the building or land not less than 14 days notice of its intention to exercise that right and, in a case falling within sub-paragraph (a), (d) or (e), together with any appropriate plans specifying the remedial works proposed to be carried out. Such notice must contain a statement which notifies the recipient of his right under paragraph (6) to make a referral to arbitration.
(6) Where a notice is served under paragraph (5)(a), (d) or (e), the owner and or occupier of the building or land concerned may, by serving a counter-notice within the period of 14 days beginning with the day on which the notice was served, require any issue as to whether the remedial works proposed by the undertaker are sufficient to fulfil their purpose, or it is necessary or expedient to carry out the remedial works or to enter the building or land to be referred to arbitration under article 63 (arbitration).
(7) The undertaker shall compensate the owners and occupiers of any building or land in relation to which rights under this article have been exercised for any loss or damage arising to them by reason of the exercise of those rights.
(8) Where—
(a)remedial works are carried out under this article to land or a building; and
(b)within the period of 5 years beginning with the day on which the authorised project carried out in the vicinity of the land or building first comes into use it appears that the remedial works are inadequate to protect the land or building against damage caused by the carrying out or use of that part of the authorised project,
the undertaker shall compensate the owners and occupiers of the land or building for any loss or damage sustained by them.
(9) Nothing in this article shall relieve the undertaker from any liability to pay compensation under section 10(2) of the 1965 Act (compensation for injurious affection).
(10) Any compensation payable under paragraph (7) or (8) shall be determined, in case of dispute, under Part 1 of the 1961 Act (determination of questions of disputed compensation).
(11) In this article “remedial works” in relation to land or a building means any monitoring or works the purpose of which is to remedy any damage which has been caused, or prevent any further damage which may be caused, by the carrying out, maintenance or use of the authorised project.
(12) Without prejudice to the definition in article 2 (interpretation) the definition of “building” shall for the purposes of this article include apparatus, equipment, or apparatus or equipment within any building.
(13) In this article “plans” means reasonable and appropriate documents demonstrating conclusion of the undertaker’s assessment that it is necessary or expedient to carry out the remedial works and that the remedial works proposed by the undertaker will be sufficient to fulfil their purpose.
(14) The undertaker may enter into an agreement or agreements in respect of remedial works with any owner or occupier (with the requisite consent of the owner) of a building to which this article applies or of any other building likely to be affected by the authorised project and such agreement shall have the effect (as between those parties only) of regulating the powers in this article, insofar as they incorporate, add to, omit or modify the provisions of this article or any of them.