In advance of his visit to the UK next week, the Brexiters have a new target in their sights: Barack Obama. Nigel Farage has described him as "the most anti-British American president there has ever been" (James Madison, who declared war on the UK in 1812, may contest that), adding that he hopes he will be replaced by someone "rather more sensible when it comes to trading relationships with this country". Boris Johnson has denounced Obama as "plainly hypocritical".

The cause of the Brexiters' ire is the US president's intention to repeat his view that the UK should remain in the EU. Many regard it as illegitimate for him to hold an opinion on the referendum (though they are rarely shy of offering theirs on his country and appear remarkably relaxed by Donald Trump's intervention). To regret Obama's behaviour is one thing, to actively attack it is another.

Tory MP Jacob Rees-Mogg has suggested that the US president's stance "helps Brexit". The evidence suggests not. As Sunder Katwala, the director of British Future, has noted, Obama is, and has long been, popular in the UK. Polled by Pew Resarch in June 2015, 76 per cent of British voters trusted him "to do the right thing regarding world affairs" (and most probably judge the US to have a passing interest in our EU membership). In September 2014, YouGov found that he had a net approval rating of +49 in the UK, compared to David Cameron's -12. Rees-Mogg's belief that the public will "[not] want to be told what to do by a rather unsuccessful American president" looks hopeful at best.

The Leave side should behave with dignity during Obama's final UK visit as president - and hope that few notice his intervention. By attacking him, they only lend greater prominence to it. And for Farage - one of the most unpopular politicians in the country - to do so, only serves to confirm that he is the Remain side's not-so secret weapon.