Barack Obama flew into a storm of protest last night over his decision to urge Britain to stay in the EU.

Senior Eurosceptic MPs also vented their fury at the Prime Minister and Defence Secretary over a warning that there would be celebrations by Moscow and the Islamic State ‘in Raqqa’ if the UK voted for Brexit.

No 10 and the White House have orchestrated a pro-EU blitz to coincide with the US President’s visit.

Mr Obama last night urged Britain not to cut its ties with Brussels – saying it 'magnified' the UK's influence in the world

President Barack Obama has arrived in London for a three-day visit that will include dining with the royal family and talks with Prime Minister David Cameron

The sacrifice of GIs during the Second World War means America also has a stake in the referendum debate, he said.

The US president told British voters their choice 'will echo in the prospects of today's generation of Americans as well'.

No 10 and the White House have orchestrated a pro-EU blitz to coincide with the US President's visit. Mr Obama said a vote to cut ties with Brussels will leave Britain less able to tackle terrorism, the migration crisis and economic difficulties.

And he said Britain and America's 'special relationship was forged as we spilled blood together on the battlefield'.

'I will say, with the candour of a friend, that the outcome of your decision is a matter of deep interest to the United States,' the president wrote in the Daily Telegraph.

'The tens of thousands of Americans who rest in Europe's cemeteries are a silent testament to just how intertwined our prosperity and security truly are. And the path you choose now will echo in the prospects of today's generation of Americans as well.'

President Obama said the US, the UK and the EU 'have turned centuries of war in Europe into decades of peace, and worked as one to make this world a safer, better place'.

'What a remarkable legacy that is,' he wrote. 'And what a remarkable legacy we will leave when, together, we meet the challenges of this young century as well.'

The President also made an emotional appeal for Britain to vote to remain a part of the EU, which he says is an institution created 'from the ashes of war'.

'Our special relationship was forged as we spilled blood together on the battlefield,' he said. He compared the EU to the United Nations, Nato and post-war agreements such as Bretton Woods and the Marshall Plan.