Police officer guarding 10 Downing Street entrance gate in the City of Westminster. Brexit, Britain, London, Officer, Theresa May, UK, architecture, attraction, british, building, capital, city, conservative, control, crisis, downing, downing street, election, england, english, european, famous, fence, gate, house, kingdom, landmark, leader, minister, political, politician, politics, power, prime, protection, residence, safety, security, street, terror, terrorism, travel, westminster, whitehall