Liam Fox and Boris Johnson are locked in a bitter Whitehall feud over who controls key parts of Britain's foreign policy, a leaked letter seen by The Telegraph reveals.

Just weeks after the two men joined the Government, Dr Fox sent Mr Johnson the terse letter, which he copied to Theresa May, effectively demanding that the Foreign Office be broken up.

Dr Fox, suggested that British trade with other countries would not "flourish" if responsibility for future policy remained with the Foreign Office.

He also listed a series of economic statistics which called into question the Foreign Office's ability to boost Britain's economic ties with other countries and suggested that Mr Johnson focused instead on "diplomacy and security" including overseeing MI6 and GCHQ.