David Miliband today warned President Medvedev not to provoke a new Cold War with the West but said that it would be counter-productive to try to isolate Russia for its actions and continued military presence in Georgia.

In a speech to students in the Ukrainian capital Kiev, Mr Miliband said that the sight of Russian tanks in Georgia had come as a "rude awakening". He also accused Mr Medvedev of trying to "redraw the map" of the Caucasus through his unilateral recognition of the breakaway provinces of South Ossetia and Abkhazia.

"The Russian President says he is not afraid of a new Cold War," Mr Miliband said. "We don’t want one. He has a big responsibility not to start one."

Mr Miliband said that he had come to the Ukraine to demonstrate his support for the former Soviet republic, seen by some observers as the next possible target of Russian nationalism and aggression.

Like that in Georgia, the pro-Western government in Kiev wants to join Nato and the European Union — moves firmly opposed by Moscow.

"I want to re-affirm the commitment of the United Kingdom to support the democratic choices of the Ukrainian people," Mr Miliband said. "My visit is designed to send a simple message: we have not forgotten our commitments to you. Nor shall we do so."

The Foreign Secretary said that events in Georgia had ended the period of post-Cold War calm in Europe.

"The Georgia crisis has provided a rude awakening. The sight of Russian tanks in a neighbouring country on the 40th anniversary of the crushing of the Prague Spring has shown that the temptations of power politics remain," he said.

"The old sores and divisions fester. And Russia is not yet reconciled to the new map of this region. Yesterday’s unilateral attempt to redraw the map marks a moment of real significance. It is not just the end of the post-Cold War period of growing geopolitical calm in and around Europe. It is also the moment when countries are required to set out where they stand on the significant issues of nationhood and international law."

Mr Miliband said that the West would not allow the Kremlin to prevent countries such as Georgia and Ukraine joining Nato.

"In Nato, we will stand by our commitments to existing members, and there will be renewed determination that there should be no Russian veto on the future direction of Nato," he said.

While Russia had demonstrated its undoubted military might in Georgia, he made clear that there would be a price to pay politically for its actions.

"Today Russia is more isolated, less trusted and less respected than two weeks ago. It has made military gains in the short term. But over time it will feel the economic and political losses," he said.

"If she truly wants respect and influence, and the benefits which flow from it, then Russia needs to change course."

However he rejected calls for the international isolation of Russia, and urged instead a new policy of "hard-headed" engagement with Moscow.

"Isolation is not feasible — Russia is too enmeshed in the world economy," he said. "It would be counter-productive — its economic integration is the best discipline on its politics. It would only strengthen the sense of victimhood that is the fuel for intolerant nationalism."

However he said that Britain and its Western allies needed to "rebalance" their energy relationship with Moscow so that in future they would be less dependent on Russia.

Mr Miliband dismissed Vladimir Putin’s assertion that the collapse of the old Soviet Union had been the "greatest geopolitical catastrophe" of the 20th century. "It will only be a tragedy for Russia if it spends the next 20 years believing it to be the case," he said.

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