UK 22 April 2016 Barack Obama delivers a hammerblow to the Brexiters The US president demolished the Leave campaign's economic boasts as he warned the UK would go to "the back of the queue" for trade deals. Getty Images. Sign UpGet the New Statesman's Morning Call email. Sign-up For years, opponents of the EU have boasted of how the UK would flourish after leaving. Liberated from the Brussels yoke, they said, Britain would be free to cut trade deals with the US and others. Today, they were hit by the world's biggest boomerang. At his Foreign Office press conference with David Cameron, Barack Obama didn't confine himself to banal remarks about UK "influence". He delivered a hammerblow to the Brexiters. Britain, he warned, would go to "the back of the queue" for a US trade deal if it left - a gift to the Remain campaign. The use of the English "queue", as opposed to the American "line", will only enhance its impact on swing voters anxiously contemplating the cost of withdrawal. Challenged during the Q&A on whether it was legitimate for him to voice his support for the UK's EU membership, Obama seized his moment. "My understanding," he dryly remarked, "is that some of the folks on the other side have been ascribing to the United States certain actions we’ll take if the UK does leave the EU. So they say, for example, that 'well, we’ll just cut our own trade deals with the United States'.. So they’re voicing an opinion about what the United States is going to do and I figured you might want to hear from the President of the United States what I think the United States is going to do. "And on that matter, for example, I think it’s fair to say that maybe some point down the line there might be a UK-US trade agreement, but it’s not going to happen any time soon because our focus is in negotiating with a big bloc—the European Union—to get a trade agreement done." "And the UK is going to be at the back of the queue. Not because we don’t have a special relationship but because, given the heavy lift on any trade agreement, us having access to a big market with a lot of countries, rather than trying to do piecemeal trade agreements, is hugely inefficient." The Brexiters will reply that the UK isn't even in the queue for a trade deal at the moment (if one discounts the EU-US negotiations). They will point out that Obama has less than a year left in the White House (though Hilary Clinton, his likeliest successor, takes an identical stance). They will accuse him of "bluffing", of "bullying", of joining "Project Fear". None of this will disguise how wounding this intervention is. When a US president speaks on the UK, voters listen. When that president is hugely popular (as Obama is), many will agree. It is the economy, more than any other issue, that will likely determine the outcome on 23 June - and Obama today fired a precision-guided missile at the Brexiters' base. There was much to cherish during the hour-long press conference: Obama's patient explanation of why the White House didn't need two Churchill busts (one having been returned - replaced by Martin Luther King), his eulogy for Prince (can somebody book him for Desert Island Discs?) and his relaxed smile in response to Boris Johnson's demagogic remarks on his "part-Kenyan" heritage. But it is his "back of the queue" warning that will be repeatedly played before the referendum. David Cameron could not have asked for a better farewell present. › Are we sex-literate? Why we should all be writing more about pleasure George Eaton is senior online editor of the New Statesman. Subscribe For daily analysis & more political coverage from Westminster and beyond subscribe for just £1 per month!