I spent a fair sum of money buying this old envelope. No, no, no. I haven't gone el loco just yet. This envelope is important. I have talked about the time when Brunei did not use Brunei stamps. This envelope is proof of one of those times.
For about a year after the British took over Brunei (or as the Australians would claim, it was the Ozzies and not the Brits) from the Japanese in 1945, the British Military Administration had to get a semblance of normal life back including running the Postal Service. The British could not use the local Brunei stamp stocks as those had been overprinted by the Japanese. So they used North Borneo (Sabah) stamps or Sarawak stamps and overprinted those with the words BMA which stands for British Military Administration.
This envelope written by someone in Brunei to someone named Clueit in Manchester. He used those stamps that I had mentioned. The stamps were postmarked 1946. It wasn't until the year after in 1947 did Brunei stamps came back.