The long-awaited security backing paper has arrived. Ian Billings reported the first sighting on his blog, and his latest update here shows six stamps reissued on the new paper. It's interesting that the stamps on security paper are all 2015 dates, but the first five 2016 stamps are on plain backing paper. These may get reissued on security paper if another printing is needed.
There are a lot of interesting comments on Ian's first report. I suggest you scroll down and read them. Glenn Morgan makes the interesting point that once this paper becomes ubiquitous, it will be very easy to identify a counterfeit in court. As we know, some of today's counterfeits look very much like the real thing, and showing the difference compared with a genuine stamp to a judge or jury could be problematic.
This assumes, of course, that counterfeiters won't be able to find a way to simulate this backing paper to something that looks close enough. We will soon see.
Contrary to the suggestions by some of the commenters, I do not believe that this is a scheme to raise money from collectors. That's what 18 Star Wars stamps are for. I also believe that there may well be some people who do want to use genuine stamps and will appreciate being able to easily identify and avoid counterfeits.
I do, however, agree with the commenter who said that Royal Mail is losing a lot of money by not canceling stamps on mail. Just the other day, I received a packet from the UK with a lovely, single £2.25 purple stamp. There was not a mark on the packet. The stamp won't get reused because I will destroy it, but if it had been canceled it would have been a nice cover to save. (And I'm not suggesting biro cancels, as Roy showed in the previous post.)
And we need an initialism (not acronym - look it up) for this new paper and, therefore, for the old, plain paper. Borrowing from what Ian Billings used on his recent post, I suggest SBP for security backing paper and PBP for plain backing paper. We'll see what the other Machin chroniclers come up with.