Post Office Act, 1908

Official mark to be evidence of amount of postage.

9. The official mark of any sum on any postal packet as due to the Post Office, British, colonial, or foreign, in respect of that packet, shall in every British court, whether within or without the United Kingdom, be received as evidence of the liability of the packet to the sum so marked, and the sum shall be recoverable in any such court as postage due to His Majesty.