The West must rearm to take part in a new Cold War with Russia, a senior Conservative has said.
Lord Spicer, a former minister and chairman of the 1922 Committee of Tory backbench MPs, said that economic sanctions against Vladimir Putin had not worked.
His comments came as former head of the Royal Navy Lord West of Spithead warned Russia was building up its weapons and in a way that would have made people "terrified" during the Cold War.
Lord Spicer hit out at question time in the House of Lords at the effectiveness of the response to Russia's occupation of Crimea.
"Is not the stark reality that so far diplomacy has failed, that economic sanctions have made Mr Putin more aggressive than less and that the West will have to be prepared to engage in a cold war with Russia and to rearm accordingly?" he asked Foreign Office minister Baroness Anelay of St Johns
Lady Anelay told him: "I don't adopt your route to rearming and I'm not as pessimistic.
"Perhaps it is because I am ever hopeful and I am clearly impressed by the diplomacy delivered by our own Foreign and Commonwealth Office and by our colleagues throughout the European Union and the United Nations and the Commonwealth all of whom have a common view.
"Yesterday the Prime Minister met with the German Chancellor Angela Merkel and in his press release has made it clear we continue to stand by Ukraine."
Labour peer Lord West, who was chief of defence intelligence from 1997 to 2001, and First Sea Lord from 2002 to 2006, said there had been a "huge increase in Russian defence expenditure".
"In particular this whole nuclear triad, with brand new ballistic missiles, submarines, a brand new attack submarine with a new cruise nuclear weapon," he said.
"It is running its nuclear trains again. All of the indicators that during the Cold War would have had me terrified as chief of defence intelligence."
He said Mr Putin's policy of de-escalation was in fact a policy of "nuclear escalation".
"Is it not time to inject a real sense of urgency into these talks," he said. "We are getting near misses constantly over the Baltic. Things are really, really very risky indeed.
"We need to have proper talks fully involving the Russians, who have a very real and proper interest in the Ukraine I believe."
He added: "We need to get this going very quickly with everyone involved, the Russians involved, otherwise we might move towards a scenario that none of us would like."
Lady Anelay said she sympathised and talks expected next week would involve the Russians.
"The Russians are feeling the brunt of sanctions, as they should, for their illegal occupation of Crimea and for what they are dong in sending in their troops in East Ukraine and making the humanitarian situation there worse," she said.
"Diplomacy can be a strong tool - let's make sure it is."