Extension of value by postage stamps

(1) The sender of a British postal order may increase its (a) on postal orders of denominations up to and including twenty-five pence by not more than two pence; and (b) on postal orders of denominations above twenty-five pence by not more than four and a half pence, by affixing this country’s postage stamps not exceeding two in number to the face of the order in the places provided. (2) Stamps perforated with initials or marks or embossed, or cut-out impressed stamps shall not be valid for such purposes. 91