General Rate Act 1967

4 Where, at the date of the making of a rebate application in respect of any hereditament or part of a hereditament, the persons who reside or are usually resident in the relevant premises, that is to say—

(a) in the case of such an application as is mentioned in paragraph 1 or 2 of this Schedule, the hereditament apart from any part thereof in respect of which by virtue of the said paragraph (c) any other person is entitled to make a rebate application ;

(b) in the case of such an application as is mentioned in paragraph 3 of this Schedule, the part of the hereditament in respect of which the application is made,

include (apart from any child or children) any person in addition to the applicant and one other person who is either the spouse or a relative of the applicant, then, subject to paragraph 6 of this Schedule, the applicant's reckonable rates shall be reduced by an amount bearing the same proportion to the amount of the reckonable rates as the number of those additional persons bears to the total number of persons who at the said date reside or are usually resident in the relevant premises (any child who is not a child of the applicant or in the applicant's care being disregarded and any child not falling to be disregarded being counted as half a person).