Police officers survey the area from the roof of Buckingham Palace in central London on June 3, 2019, ahead of the arrival of the US President Donald Trump and US First Lady Melania Trump on the first day of their day State Visit to the UK. - Britain rolled out the red carpet for US President Donald Trump on June 3 as he arrived in Britain for a state visit already overshadowed by his outspoken remarks on Brexit. (Photo by Daniel LEAL-OLIVAS / AFP)