Former CIA boss: Brexit will '˜swim against the tide of history'

John O Brennan, who served as director of the CIA for four years until President Donald Trump’s inauguration, said the relationship between British and US intelligence agencies would not be damaged by Brexit but it will be a bumpy process for the UK to disengage from European Union.

He said: “Right after the Brexit vote Alex Younger, the head of MI6, called me and assured me there would be no change whatsoever in the relationship between MI6 and the CIA and between British intelligence services and their US counterparts, and I assured him the same would be true from the US side.

“Our British partners are our closest intelligence and security partners bar none and we do so much with them.

“While I do have concerns about the UK separating from Brexit I’m confident that the relationship that has developed between US and British intelligence and security professionals over the past 75 years is going to continue and become even stronger.”

Asked if it was possible to have the truly global Britain, which Prime Minister Theresa May has spoken of, he said: “Reversing course is going to be very challenging, there undoubtedly will be hiccups.

“I think it is swimming against the tide of history, I really do think, and I’ve seen that this world has become much more connected and inter-dependent and the forces of isolationism and protectionism, we’ve seen in history, they have not worked out the way people wanted.

“We all learn lessons and I hope the very best for the people of the United Kingdom.”

Mr Brennan, who will deliver the annual Richard Dimbleby lecture today, added: “I am looking at the issue of making sure that countries and governments do not react emotionally and impulsively to some of the recent challenges associated with globalism.

“It’s the will of the British people to separate from the EU but if I look back over the last 60 years of how far the EU has come and what it’s contribution has been to European security and political goals and objectives and economic development I think it has been essential.

“The UK plays such a primary role in European affairs and indeed global affairs and so while some may see the benefits of separation, the EU as a collective, as a group of European countries and peoples that are trying to optimise their influence in the world, I think reversing the course that the EU has been on for 60 years is one that is not going to be beneficial to either the collective or the counties that take that course.

“I could be wrong but it’s a major undertaking, it has lots of ramifications and while some things sound good and even simple, sometimes simple solutions to complicated problems are not advantageous.”

Mr Brennan added he will also be discussing “issues relating to leadership” in his lecture, which will be broadcast on BBC One.

He said of President Donald Trump: “I’m hoping there is going to be a steep learning curve because these issues are complicated and I’m hoping Mr Trump and others take time to understand that and understand what the implications of the policy courses that may be considered.”

He continued: “There are a lot of fears and anxieties associated with the movement of new peoples into societies but it’s important for governments to recognise that building walls between countries and embarking on protectionist and isolationist policies is very short-sighted in my view.

“This world has become a much more inter-connected world as a result of technology changes and I think if anyone tries to reverse that course of globalization they are really running directly into the winds of progress.”

The Richard Dimbleby Lecture 2017 will be broadcast on BBC One today at 10.45pm.