Post Office Act, 1908

Stamping paper for envelopes, &c. provided by private persons.

11. The Commissioners of Inland Revenue may, under regulations made or sanctioned by the Treasury, stamp any paper sent to them for the purpose of being stamped as covers or envelopes of letters or packets with stamps denoting the several rates of postage on payment of the amount of the stamps required to be impressed on the paper, and (unless the amount exceeds ten pounds) upon payment of such fee in addition as the Treasury may direct.

Conditions of Transit of Postal Packets.