“Incoherent, inconsistent, hypocritical” – so says leading Leave campaigner Boris Johnson about President Barack Obama’s comments on Britain’s Brexit referendum in a UK newspaper.

Between Royal dinners and official engagements Obama found a moment to say his piece on an EU exit.

“The European Union doesn’t moderate British influence – it magnifies it. A strong Europe is not a threat to Britain’s global leadership; it enhances Britain’s global leadership.”

Prime Minister David Cameron, campaigning for the UK to stay in the EU, welcomed Obama’s statements: “The US is one of our closest allies. So it’s important to hear Barack Obama on why we should remain in the EU,” he tweeted.

“As the president said this morning in his piece in the Daily Telegraph, America sees it very much as a question of tidying the European continent after the horrors of the Second World War, the need to ensure the peace is maintained. I think the difficulty is the European Union is now causing such stresses and strains that actually remaining in is the insecure option,” responded Mayor of London Boris Johnson in a wide-ranging rebuttal.

Johnson reminded America that it had not ratified the international law of the sea, the UN’s female emancipation and rights of the child conventions, and nor did it recognise the ICC/ He said that was evidence of America’s “hysterical jealousy” in guarding its own democracy.