Russia is now “indisputably” a greater threat to the security of Britain and her allies than Islamist extremist groups such as al-Qaeda and Islamic State in Iraq and the Levant (Isil), the new Army chief has warned.

Apart from posing a conventional military threat, the Russians are constantly seeking to undermine the West by developing new war-fighting capabilities in non-conventional areas such as cyber and space.

Speaking in his first interview since his appointment as the Chief of the General Staff, Gen Mark Carleton-Smith, 54, said it was vital that Britain and its allies were not complacent about the threat Russia posed.

“Russia today indisputably represents a far greater threat to our national security than Islamic extremist threats such as al-Qaeda and Isil,” he said.

“Russia has demonstrated that it is prepared to use military force to secure and expand its own national interests. The Russians seek to exploit vulnerability and weakness wherever they detect it.”