Theresa May has pledged to urge Britain’s European neighbours to spend more on their militaries, following a meeting with Donald Trump.

After bilateral talks with the President in Washington DC Ms May moved to placate concerns voiced Mr Trump about Europe being ill-equipped to fight a war.

At a joint press conference in the White House Ms May said that Mr Trump backs the Nato alliance “100 per cent”, though the US President made no personal confirmation of this claim. He recently branded aspects of the Cold War alliance “obsolete”.

Ms May said Britain and the United States were united in recognising Nato as the “bulwark and collective defence” of the West.

Mr Trump has previously suggested that he might not come to the military aid of European states that did not spend the 2 per cent of GDP Nato target on defence.

Ms May told journalists: “I’ve agreed to continue my efforts to encourage my fellow European leaders to deliver on their commitments to spend 2 per cent of their GDP on defence so the burden is more fairly shared.”

She added: “Today we have reaffirmed our unshakeable commitment to this alliance.”

“Mr President, I think you confirmed that you are 100 per cent behind Nato.”

Figures collated in 2016 show just five of the 28 Nato countries spend enough to meet the 2 per cent target.

The PM said: “We are discussing how we can work even more closely together in order to take on and defeat Daesh and the ideology of Islamist extremism wherever it is found.”

She said there would be deeper intelligence and security cooperation between the UK and the US including measures to counter the terror group in cyber space.

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It is not clear how Ms May intends to convince European countries to spend more on defence. She herself faces a daunting negotiation with the European Union over Brexit.

Mr Trump himself hailed the “special relationship” between the UK and the US.