a local authority has carried out remedial operations in relation to that tip or has carried out any such exploratory tests as are referred to in section 23(1)(a); and

the owner has served on the local authority a claim for compensation under section 20 in respect of damage or disturbance resulting from the carrying out of those exploratory tests or remedial operations; and

either no order for contribution has been made under section 19 in respect of the expenses otherwise falling to be borne by the owner in respect of the carrying out of those exploratory tests or remedial operations or one or more such orders have been made but the specified percentage or, as the case may be, the aggregate of the specified percentages is less than 100.

the expenses in respect of which a contribution may be claimed under section 21 or section 23 include expenses incurred in carrying out remedial operations or any such exploratory tests as are referred to in subsection (1) or subsection (2) of section 23; and

the contributory has served on the owner of the disused tip or, as the case may be, the local authority concerned a claim for compensation under section 20 in respect of damage or disturbance resulting from the carrying out of those exploratory tests or remedial operations.