LONDON, ENGLAND - MARCH 23:  Prime Minister Theresa May leaves Downing Street on March 23, 2017 in London, England. The British Prime Minister Theresa May spoke last night after a terrorist attack took place in Westminster, saying Parliament would meet as normal today and "We will come together as normal".  PC Keith Palmer and three others lost their lives in the attack and the perpetrator was shot dead by police.  (Photo by Jack Taylor/Getty Images)