The foreign secretary has claimed that western powers failed to fence in Putin as they “let down” their guard in the wake of the Cold War.

Truss told the Sun newspaper that Vladimir Putin’s 2014 annexation of Crimea was not responded to adequately as the West  “let down our guard” following the demise of the USSR..

Truss argued that the UK ought “not be trying to negotiate” with Putin or offer him a “way out”.

“Because of that failure to act then, we are now facing these very high costs, and the cost will get only worse,” she went on.

“The Foreign Office abandoned our information unit and we have been flooded by Russian disinformation. We became too dependent on authoritarian regimes.”

Truss also signalled her approval of Germany’s ramping up of defence spending following decades of decline, and stressed that Ukrainians were fighting “freedom and democracy” as well as their nationhood.