Spotlight: Obama calls on Britons to stay in EU, gives trade warning against Brexit

Visiting U.S. President Barack Obama on Friday appealed to the British to stay in the European Union (EU), warning that Britain would "go to the back of the queue" to strike a bilateral free trade deal with the United States if Brexit proponents win the June 23 referendum.

Standing alongside British Prime Minister David Cameron at the Foreign Office in London, Obama spoke of the impact of an "out" vote in Britain's national referendum on continued membership in the EU.

"If one of our best friends is in an organization that enhances their power, enhances their economy ... I want them to stay in it," said Obama.

Talking about a possible bilateral free trade deal between the United States and Britain if Britons vote to withdraw from the EU, Obama said the United States prioritizes negotiating the Transatlantic Trade and Investment Partnership with the EU instead of bilateral trade with a single European country.

"I think it's fair to say that maybe some point down the line there might be a UK-U.S. 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. The UK is going to be in the back of the queue," Obama said.

"Right now, I've got access to a massive market, where I sell 44 percent of my exports. And now, I'm thinking about leaving the organization that gives me access to that market, and that is responsible for millions of jobs in my country and responsible for an enormous amount of commerce and upon which a lot of businesses depend, that is not something I would probably do," Obama said.

Cameron, who is leading the "Remain" campaign, defended Obama's right to voice his opinion on Britain's choice. "I think it's right to listen to, and consider, the views of your friends," he said.

"When it comes to the special relationship between our countries, there's no greater enthusiast than me ... But I've never felt constrained in this relationship by the fact that we're in the European Union," the prime minister said.

In his previous remarks during the London trip, Obama argued that the EU magnifies Britain's global influence, instead of moderating it.

"The EU has helped spread British values and practices -- democracy, the rule of law, open markets -- across the continent and to its periphery ... As your friend, I tell you that the EU makes Britain even greater," Obama wrote in The Daily Telegraph.

"A strong Europe is not a threat to Britain's global leadership; it enhances Britain's global leadership," he added.

The president also stressed the important role Britain has been playing in the EU, saying Britain has made the bloc stronger.

"The United States sees how your powerful voice in Europe ensures that Europe takes a strong stance in the world, and keeps the EU open, outward-looking, and closely linked to its allies on the other side of the Atlantic," Obama wrote.

He also candidly admitted that Britain's EU membership is of "deep interest to the United States."

"The path you choose now will echo in the prospects of today's generation of Americans ... The U.S. and the world need your outsized influence to continue -- including within Europe," he said.

Analysts believe Obama's appeal might help the "Remain" camp, which currently has a 54-percent support rate as opposed to the 46 percent for "Leave."

However, Obama's bold move has also drawn strong criticism from Brexit campaigners, accusing him of intervening another country's domestic affairs.

Brexit supporters accused the U.S. president of being guilty of "wanton double-standards," saying that he was asking the British to do something he wouldn't dream of asking Americans.

London Mayor Boris Johnson, a leading Eurosceptic, said it was "downright hypocritical" of the United States to intervene in Britain's debate.

"For the United States to tell us in the UK that we must surrender control of so much of our democracy is a breathtaking example of the principle of do as I say, not as I do," he wrote in The Sun.

Justice Minister Dominic Raab, another leading figure in the Leave campaign, said Britons should consider their own interests instead of the Americans'.

"He (Obama) argued that he thinks it is in America's interests for the UK to stay in the EU, but what is good for U.S. politicians is not necessarily good for the British people," Raab said.

Obama is paying a dual-purpose visit to his closest ally, offering personal greetings to Queen Elizabeth II for her 90th birthday, as well as trying to convince Britons not to leave the EU. Endi