Lord David Cameron has warned the UN about the consequences of withdrawing support for Ukraine in its war against Russia.
The foreign secretary was speaking to the United Nations General Assembly in New York on the eve of the second anniversary of the invasion.
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Lord Cameron said: “Two years on, I recognise some want to rethink. There is a sense of fatigue, there are other problems, a compromise might seem attractive.
“But this is wrong.
“We must recognise the cost of giving up.
“Putin has said there will be no peace until Russia’s goals are achieved, and in his recent interview, he studiously avoided confirming he was satisfied with the land seized from Ukraine at present.
“This is not a man seeking compromise – rather, this is a neo-imperialist bully who believes that might is right.”
He added that, if President Putin were to “eke out some kind of win, the rest of the world would suffer too”.
Lord Cameron started his speech by saying he warned about the dangers of Vladimir Putin in 2008, when he was leader of the opposition, and Russian troops entered South Ossetia in Georgia.
And he spoke of how he was prime minister in 2014 when Putin’s “little green men” entered Crimea.
“I said that if we did not stand up to Putin, he would be back for more,” the foreign secretary told the UN.
“Now, having tried and failed to conquer all of Ukraine, the lesson of this history is clear. If we do not stand up to Putin, he will be back for more.”
He added that he believes the world “has started properly to wake up to Putin’s menace”.
Lord Cameron went on to criticise the Russian leader’s “ahistorical claim” Ukraine’s existence “is anti-Russian”.
“I claim which runs contrary to the principle of self-determination – One of the foundations of the United Nations.”
The foreign secretary criticised the Russian claims that Western nations are “somehow out to dismember Russia” – a “central lie” in the conflict as he and other leaders spent years trying to build relationships with Moscow.
“We did that because we profoundly believe that a secure, stable Russia, at peace with its neighbours, is in our interests and the world’s,” he said.
“It is a tragedy that Putin prefers to hark back to the ninth century to justify aggression rather than taking up this offer of a different path.”
The secretary went on to explain why he believes “we must stay strong”.
A “win” in Ukraine for Putin “would not end there”.
“Putin could easily apply his distortions of history elsewhere, such as Moldova or the Baltic States, and others will be emboldened to turn to fighting when it suits them,” Lord Cameron said.
“No country with a large, aggressive neighbour would be safe.”