Talks in Geneva today between officials from the United States and Russia mark the start of a flurry of diplomatic activity aimed at reducing tensions over Ukraine. They will be followed by discussions between Russia and Nato members and a gathering of the Organisation for Security and Co-operation in Europe in Vienna later this week. But a meeting of minds seems unlikely given the disparate nature of the demands.

Vladimir Putin’s sabre-rattling over Ukraine, with Russian forces gathered on the eastern border, is intended to pressurise Nato into stopping its expansion eastwards.

Since 1990 many former Warsaw Pact nations have joined the military alliance to the alarm of the Kremlin, which has drawn the line at the prospect of Ukraine seeking membership.

But in insisting that Nato takes on no new members, Mr Putin has overstepped the mark. Sweden and Finland, two Nordic countries that have remained outside the alliance, now say they might join because of the threat posed by Russia. For Finland, this is a fear well attested by history and one reason why the country has rarely taken any strategic decisions without consulting Moscow.

Russia’s foreign ministry says Finland and Sweden joining Nato “would have serious military and political consequences that would require an adequate response from the Russian side”. But these are free, democratic countries that cannot and will not be browbeaten by President Putin provided they are given full support by the rest of Nato.

The problem is that no one is sure how committed countries like Germany, which is beholden to Russia for its gas supplies, are to the cause of Nato expansion. Whether Europe is really prepared to stand up to Mr Putin will become clearer this week.