The erection, construction or carrying out, or maintenance, of any building or work on land which has been acquired or appropriated by a local authority for planning purposes, whether done by the local authority or by a person deriving title under them, is authorised by virtue of this section if it is done in accordance with planning permission, notwithstanding that it involves interference with an interest or right to which this section applies, or involves a breach of a restriction as to the user of land arising by virtue of a contract:

Provided that nothing in this subsection shall authorise interference with any right of way or right of laying down, erecting, continuing or maintaining apparatus on, under or over land, being a right vested in or belonging to statutory undertakers for the purpose of the carrying on of their undertaking.

This section applies to the following interests and rights, that is to say, any easement, liberty, privilege, right or advantage annexed to land and adversely affecting other land, including any natural right to support.

In respect of any interference or breach in pursuance of subsection (1) of this section, compensation shall be payable under section 63 or 68 of the [1845 c. 18.] Lands Clauses Consolidation Act 1845 or under section 7 or 10 of the [1965 c. 56.] Compulsory Purchase Act 1965 to be assessed in the same manner and subject to the same rules as in the case of other compensation under those sections in respect of injurious affection where the compensation is to be estimated in connection with a purchase under those Acts or the injury arises from the execution of works on land acquired under those Acts.

Where a person deriving title under the local authority by whom the land in question was acquired or appropriated is liable to pay compensation by virtue of subsection (3) of this section, and fails to discharge that liability, the liability shall be enforceable against the local authority:

Provided that nothing in this subsection shall be construed as affecting any agreement between the. local authority and any other person for indemnifying the local authority against any liability under this subsection.

Nothing in this section shall be construed as authorising any act or omission on the part of any person which is actionable at the suit of any person on any grounds other than such an interference or breach as is mentioned in subsection (1) of this section,