Two of Nato's most respected retired generals will on Wednesday issue a stinging indictment of European military capabilities, arguing that unless the continent pools its defence resources it may be unable to meet mounting security risks such as international terrorism.

Gen Joseph Ralston, the retired US officer who headed Nato until 2003, and retired General Klaus Naumann, Germany's former chief of defence and head of Nato's military committee, argue that European leaders have “lacked the political will” to improve military capabilities. “Failure to meaningfully improve Europe's collective defence capabilities in the coming years would have profoundly negative impacts on the ability of European countries to protect their interests, the viability of Nato as an alliance, and the ability of European countries to partner in any meaningful way with the US,” according to the report, a copy of which was obtained by the Financial Times.