This post is for my own benefit as much as anything else. I worked in pre-press for quite a while and at one point I knew all of the various sizes of paper off by heart as it was my job to not only order in the paper stock, but at times to also guillotine it up. Whenever I get a request to set up an A1 poster though I just cannot seem to keep the figures in my head and end up consulting Wikipedia. I am never too convinced at the accuracy of Wikipedia though, so in this case I have looked it up from an actual book (retro) and created a definitive list for UK folks anyway, of paper sizes.