Britain and its allies are facing a “deadly quartet” of China, Russia, Iran and North Korea who are acting together against the west, according to the newly appointed head of Labour’s defence review.

George Robertson, a former Nato secretary general, said the UK had to be prepared to take on all four if necessary, reflecting western concerns that the grouping are increasingly sharing arms, components and military intelligence.

Flanked by the new defence secretary, John Healey, Lord Robertson told a briefing that: “We’re confronted by a deadly quartet of nations increasingly working together,” and that Britain and its Nato allies have “got to be able to confront that particular quartet”.