Mr Smith said: “There’s a fair amount of evidence building up that a lot of evidence has been compromised. It’s been moved, it’s not where it lay immediately after the crash happened, and that’s very regrettable.” He said that while it might only take “a surprisingly short time” to determine what missile knocked the airliner out of the sky, he warned that “there may be some lines of inquiry that take an immensely long time to work through”.