Police search the grounds of the Gordon Arms, Fareham, Hampshire, for the body of suspected murder-victim Kevin John Palmer.
He disappeared 15 years ago.
More top news
The threat level has been raised to critical by MI5's Counter-Terrorism Analysis Centre.
Prime Minister Theresa May announced the decision from Downing Street.
Newcastle Central Mosque is welcoming Muslims and non-Muslims alike this evening to stand in solidarity with the people of Manchester.