Russia-Ukraine war live: Britain rejects Putin's spying allegations as Starmer prepares to meet Biden in Washington

Frank Gardner
Security Correspondent

Today's announcement by Russia of earlier expulsions of diplomats and the subsequent response by Britain have further increased tensions between Moscow and the West.

And yet the decisions being made now, at what many are calling a critical turning point in the war in Ukraine, must be made with a cool, clear head.

Ultimately, it comes down to this question: Should we take Vladimir Putin’s threats seriously?

There are good reasons for and against this. Every time he warned the West that he was not bluffing, it turned out that he was. He only hoped to intimidate NATO and prevent them from sending battle tanks, F16s or long-range artillery to Ukraine.

Both China, Moscow's most powerful ally, and the West have warned Russia not to even consider using nuclear weapons in this conflict.

Putin likes to remind everyone that he still has the world's largest arsenal of nuclear warheads, and that this continues to cause a stir in Washington and elsewhere.

But there are much easier and less risky ways to cause trouble for his Western opponents. For example, he hires Bulgarian criminal agents in London or arms the Houthi rebels in Yemen.

Weighing his likely response against the benefits of lifting restrictions on Ukraine will therefore be an essential part of the discussions taking place behind closed doors in Washington.