If any permanent or temporary alterations or additions to the Canal & River Trust property are reasonably necessary in consequence of the construction of a specified work, or during a period of 24 months after the completion of that work in order to ensure the safety of the Canal & River Trust property, the continued safe operation of the waterway or the prevention of a detriment such alterations and additions may be carried out by the Canal & River Trust and if the Canal & River Trust gives to the undertaker reasonable notice of its intention to carry out such alterations or additions (which must be specified in the notice), the undertaker must pay to the Canal & River Trust the reasonable cost of those alterations or additions including, in respect of any such alterations and additions as are to be permanent, a capitalised sum representing the increase of the costs which may be expected to be reasonably incurred by the Canal & River Trust in maintaining, working and, when necessary, renewing any such alternations or additions.

If during the construction of a specified work by the undertaker, the Canal & River Trust gives notice to the undertaker that the Canal & River Trust desires itself to construct that part of the specified work which in the opinion of the engineer is endangering the stability of the Canal & River Trust property or the safe operation of any waterway then, if the undertaker decided that part of the specified work is to be constructed, the Canal & River Trust shall assume construction of that part of the specified work under paragraph 27(4), pay to the Canal & River Trust all reasonable expenses to which the Canal & River Trust may be put and compensation for any loss which it may suffer my reason of the execution by the Canal & River Trust of that specified work.

The engineer must, in respect of the capitalised sums referred to in this paragraph and paragraph 27, provide such details of the formula by which those sums have been calculated as the undertaker may reasonably require.

If the cost of maintaining, working or renewing the Canal & River Trust property is reduced in consequence of any such alterations or additions, a capitalised sum representing such saving is to be set off against any sum payable by the undertaker to the Canal & River Trust under this paragraph.