(1) Where—
(a) a contract for the supply of services by 1 party to the contract (the first contractor ) on behalf of the other party to the contract (the principal ) has been discharged; and
(b) the principal enters into another contract with a person other than the first contractor for the supply of those services on its behalf by that other person (the second contractor ); and
(c) that other contract imposes an obligation on the second contractor to the effect that, so far as practicable, the second contractor shall employ, in supplying those services, persons whose employment with the first contractor ceased because of the discharge of the firstmentioned contract; and
(d) under that obligation the second contractor employs such a former employee of the first contractor; and
this section applies to that former employee.
(2) Where this section applies to a person, the aggregate of the periods of service by the person for the first contractor and the second contractor shall, for this Act, be taken to be 1 period of service for the second contractor.