The Network Rail (Thameslink 2000) Order 2006

49.  Network Rail shall be responsible for, and make good to LUL all reasonable costs, charges, damages and expenses not otherwise provided for in paragraph 46 which may be occasioned to, or reasonably incurred by, the Company—

(a) by reason of the specified works or the failure thereof; or

(b) by reason of any act or omission of Network Rail or of any person in its employ, or of its contractors or others whilst engaged upon the construction of the specified works;

and Network Rail shall indemnify the Company from and against all claims and demands arising out of or in connection with the construction of the specified works or any failure, act or omissions as aforesaid, and the fact that any act or thing may have been done in accordance with any requirement of the engineer or under his supervision, shall not (if it was not attributable to the act, neglect or default of the Company or of any person in its employ, or of its contractors or agents) excuse Network Rail from any liability under the provisions of this Part of this Schedule.