The Principal Act is amended -

(a) by inserting the following section after section 113 but in Chapter 15:

"113A. Entitlement for invalidity pension recipients.

(1) Notwithstanding this Chapter and regulations made under this Chapter old age (contributory) pension shall be payable in accordance with this section in the case of a person who-

(a) has attained pensionable age, and

(b) immediately before attaining pensionable age is in receipt of a payment under Chapter 17 of this Part.

(2) Only one pension shall be payable to or in respect of a person under this Chapter.

(3) Subject to subsection (4), old age (contributory) pension payable under this section shall be payable in accordance with the rate specified in section 111.

(4) Where a person in receipt of invalidity pension under Chapter 17 of this Part attains pensionable age and becomes entitled to a pension under this section and to a pension from another Member State, the weekly rate of pension payable shall be the greater of-

(a) the amount of pension payable, calculated in accordance with Chapter 2 or 3, as the case may be, of Title III of Regulation (EEC) No. 1408/71 [OJ No. L149, 05.07.1971, p. 2.] of the Council of the European Communities, or