There was a large element of posturing in the presentation that accompanied Vladimir Putin’s state of the union address last week, showing a mock-up missile seemingly heading for the coast of Florida. It is hard to know whether the weapons he boasts Russia has developed — including an “invincible” hypersonic missile, an underwater drone and a nuclear-powered cruise missile — really exist, or work as well as claimed. Even if they do, they would hardly change the balance of power. Yet this is still a dangerous escalation in both rhetoric and military strategy.

The Russian president was addressing a domestic audience in the run-up to an election intended to demonstrate the enduring appeal of his strongman rule. But he was also putting the west on notice, that Russia is back as a global power and determined to keep pace with the US in any efforts to expand and modernise nuclear capabilities.

Seen from Moscow, this is a reasonable response to western provocation. Mr Putin has never forgiven Nato’s encroachments on Russia’s sphere of influence. He is still bitter at George W Bush’s decision to pull the US out of the 1972 Anti-Ballistic Missile Treaty, allowing it to press ahead with a land-based missile defence system that Russia views as a direct, deliberate threat.