http://www.bbc.co.uk/news/uk-28986271 http://www.bbc.co.uk/news/uk-28986271 Home Secretary says BBC UK's terrorist threat level has been raised to 'severe', the terror threat was raised to “severe” increased activity http://www.bbc.co.uk/news/uk-28986271 Story One, http://www.bbc.co.uk/news/uk-28986271 Theresa May severe http://www.bbc.co.uk/news/uk-28986271 http://www.bbc.co.uk/news/uk-28986271 that continues to build http://www.bbc.co.uk/news/uk-28986271 severe http://www.bbc.co.uk/news/uk-28986271 UK's terrorist threat level has been raised to 'severe', severe substantial Home Secretary says http://www.bbc.co.uk/news/uk-28986271 Home Secretary says severe Raise the terror threat level