Paul Cornell announced on his blog today that there will be no solicitation for issue 16 of Captain Britain and MI:13, because issue 15 is the last one. He says a lot in his post, but he also addresses the current arc being the last and how the series will end:
Lastly, and this is really important, while we didn’t know this would be the last arc until comparatively recently, I had it in mind that it was possible it would be from the time I started plotting it. Indeed, the end of this arc marks the end of what I had planned for the book when I started. One of the images right at the finish is what I always felt I was heading towards, and I’m very pleased I got there. So: you will get a real, thorough, proper, ending, not just of ‘Vampire State’, but of the whole run. It hasn’t been rushed to fit the space, it hasn’t been compromised, it won’t just suddenly cut off: it’s what I intended. I think the Annual and the two remaining issues finish off one of my best stories in any media, and that story is actually the entirety of Captain Britain and MI-13. You’ll see what I mean a bit more next issue. This is a comic with a proper ending.
A real shame as this has been a great comic and "Vampire State" a truly fantastic story.