Spot the difference, on these 1st class red M13L from booklets of 12 coded MTIL
And in close-up
Bear in mind that it's impossible to get the microscope in exactly the same place for both stamps, but one of these is a forgery, and it's pretty convincing (oh and despite the images, the stamps are the same size!).
This Diamond Jubilee forgery, however, is easy to spot, with the iridescent printing more like the pre-issue publicity images than the real thing. The 'perforations' are so wrong it rather makes you wonder why they bothered with the elliptical perforation at all, and the portrait is just wrong!
Can anybody NOT tell which is which ?