Flight data shows that Sergei Shoigu has been travelling to and from bunkers 1,000 miles east of Moscow since the start of the invasion, as the threat of nuclear war reaches its highest level in decades.

Shoigu, 66, who is one of the chief architects of the invasion, was not seen in public for over a fortnight until last weekend, when he appeared chairing a meeting on Russia’s weapons budget.

He also appeared on Tuesday at a meeting with military officials to restate that the “liberation” of the Donbas was Russia’s primary objective. Shoigu added that Russia had degraded Ukraine’s military operations.