The idea of a European army independent of the US-led NATO alliance has been around since the early 1950s, but was largely forgotten during the Cold War. The concept reemerged with the signing of the 2007 Treaty of Lisbon, which proposed the defence integration of EU member states. Germany and France have recently come out in support of the idea.

NATO Secretary-General Jens Stoltenberg has expressed concerns over the creation of a European army, saying a European Union-only military force had the potential to “divide Europe” and overstretch the “scarce” $1 trillion in defence spending resources the alliance has at its disposal.

Speaking to The Telegraph in an interview published late Saturday, Stoltenberg insisted that he was not opposed to “more European efforts on defence,” but warned that a EU rapid reaction force like the one recently advocated for by EU foreign affairs and security policy chief Josep Borrell would be detrimental to the alliance.