The former Soviet leader, Mikhail Gorbachev, has blamed the US for the current state of relations between Russia and the West.
In a BBC interview, Mr Gorbachev said that the Russians were ready to be constructive, but America was trying to squeeze them out of global diplomacy.
He added that the Iraq War had undermined Tony Blair's credibility.
Mr Gorbachev accused America of "empire-building", which he said the UK should have warned it away from.
Moscow and the West have been in dispute over Iraq, America's plans for a missile defence system and civil rights within Russia itself.
Britain's extradition request for a Russian man in connection with the murder of ex-agent Alexander Litvinenko has also caused tension.
In an interview with Radio Four's The World This Weekend, Mr Gorbachev said relations between Russia and the West were in a bad state.
"Well, it's worse than I expected," he said through a translator.
"We lost 15 years after the end of the Cold War, but the West I think and particularly the United States, our American friends, were dizzy with their success, with the success of their game that they were playing, a new empire.
"I don't understand why you, the British, did not tell them, 'Don't think about empire, we know about empires, we know that all empires break up in the end, so why start again to create a new mess.'"
He added that the war with Iraq had damaged Britain's relationship with Russia after a promising start.
"Tony Blair and Putin established a very good relationship and that made it possible to advance our relationship," he said.
"But then Iraq happened and Tony found himself in the embrace of that military monster, of that war situation, and he lost a lot of his credibility in the world and in Europe."