Jeremy Corbyn has called for Nato to de-escalate tensions with Russia and signalled that he would downgrade Britain’s relationship with the US if he became prime minister.

The Labour leader yesterday launched his radical foreign policy pitch before the general election on December 12.

He called on Nato to focus on “reducing tensions in Europe and beyond”, ahead of the western alliance convening for a tough meeting in Watford on Wednesday as it struggles with internal divisions.

Russia’s increasing assertiveness, including its use of hybrid warfare tactics such as cyberattacks, has provoked alarm across most of Nato.

Allies on the eastern flank, including Poland and the Baltic states, are also acutely concerned about the build up of conventional Russian forces.

Britain’s national security apparatus meanwhile