(1) Where a disablement pension is payable in respect of an assessment of 100 per cent., then, if as a result of the relevant loss of faculty the beneficiary requires constant attendance, the weekly rate of the pension shall be increased by an amount determined in accordance with regulations by reference to the extent and nature of the attendance required by the beneficiary, subject to the limitation that such amount shall not exceed the amounts specified in Part IV of the second Schedule.
(2) An increase of pension under this section shall be payable for such period as may be determined at the time it is granted, but may be renewed from time to time:
Provided that no such increase shall be payable in respect of any period during which the beneficiary is receiving medical treatment as an in-patient in a hospital or similar institution.