Five unanswered questions on Keir Starmer’s Mandelson debacle

How did the PM’s chosen US ambassador fail security vetting but still get approved, what exactly did he know, and who is to blame?

Downing Street has tried to do a lot of explaining, as has Keir Starmer himself. But there are still plenty of things we do not know about how Peter Mandelson failed security vetting, and what the prime minister did or did not know about it.