On arriving in London he will find himself thrown into the monstrous hopper of the British referendum campaign, where facts are sacrificed daily on the altar of propaganda and abuse. He has been insulted by the leading Brexiteer, Boris Johnson, for suggesting that the United States would prefer Britain to remain in the EU - declared, bipartisan, American policy since time immemorial. A group of Eurosceptic MPs have warned him off intervening in the campaign. Yet, for all the fog of the Brexit wars, Obama's visit will vividly illuminate what is at stake for Britain on 23 June. The referendum will fix Britain's place in the world for a century or more.