20B.—(1) The Minister for Finance may, in writing, direct a child's allowance under section 20 to be paid throughout the child's lifetime, if satisfied—

(a) that the child is physically or mentally incapacitated to the extent of being unable to maintain himself or herself, and

(b) that the incapacity arose before the child reached 21 years of age.

(2) A child in respect of whom a direction is given under this section is entitled to be paid the allowance in accordance with the direction.]