The Manchester Arena bomber had been a “subject of interest” and opportunities to stop him were missed.

A report by former terror laws watchdog David Anderson QC, said it was conceivable the attack by Salman Abedi in May could have been avoided had “cards fallen differently”.

Internal reviews into the police and MI5’s handling of the four terrorist attacks to strike Britain this year said MI5 had on two separate occasions received intelligence on Abedi “whose significance was not fully appreciated at the time”.