Since at least May of 1923, various government departments were using stamps perforated (punctured) OHMS (On His Majesty's Service). This is a fascinating collecting area. The perforations can be found in eight possible orientations (not necessarily on every stamp type) as well as double and even triple perfs. Some are quite rate. Here are some key GVI values. We can also provide some of the scarcer varieties. Inquire.
						University Philatelics