Section 9

a right under section 2 to enforce a term (called in this section the substantive term) is subject to a term providing for the submission of disputes to arbitration (called in this section the arbitration agreement); and

the arbitration agreement is an agreement in writing for the purposes of the Arbitration Act 2001 or Part 2 of the International Arbitration Act 1994,the third party is treated for the purposes of the Arbitration Act 2001 or the International Arbitration Act 1994 (as the case may be) as a party to the arbitration agreement as regards disputes between the third party and the promisor relating to the enforcement of the substantive term by the third party.

a third party has a right under section 2 to enforce a term providing for one or more descriptions of dispute between the third party and the promisor to be submitted to arbitration (called in this section the arbitration agreement);

the arbitration agreement is an agreement in writing for the purposes of the Arbitration Act 2001 or Part 2 of the International Arbitration Act 1994; and

the third party does not fall to be treated under subsection (1) as a party to the arbitration agreement,the third party is, if the third party exercises the right, treated for the purposes of the Arbitration Act 2001 or the International Arbitration Act 1994 (as the case may be) as a party to the arbitration agreement in relation to the matter with respect to which the right is exercised, and treated as having been so immediately before the exercise of the right.