Watch: What caused the US to remove its bombers in such a hurry?

The Pentagon announced that it had withdrawn its bombers – believed to number about a dozen B-1s – from RAF Fairford, sending them back to their home bases in the United States. US media said a fresh threat prompted the move, which came after a significant incident on 27 September when police were alerted to 3 "suspicious vehicles" near the airfield. A No 10 spokesperson said helium would not remark connected "foreign nations' subject operations", but said the basal was safe. The BBC’s security correspondent Frank Gardner outlined what is known about the US decision to pull its bombers from the base. For further details, see More astir this story.