The world must prepare for “even darker days ahead” over Russia’s invasion of Ukraine, Boris Johnson has said.

Writing in The New York Times, the prime minister said Western nations have “failed to learn the lessons of Russian behaviour” that led to Vladimir Putin launching his assault last month.

“We have failed to learn the lessons of Russian aggression. For too long, we have turned the other cheek. No one can say we were not warned: We saw what Russia did in Georgia in 2008, in Ukraine in 2014 and even on the streets of Salisbury. And I know from speaking to my counterparts on recent visits to Poland and Estonia just how acutely they feel the threat.

It is no longer enough to express warm platitudes about the rules-based international order. We are going to have to actively defend it against a sustained attempt to rewrite the rules by force and other tools, such as economic coercion. We must restore effective deterrence in Europe, where, for too long, the very success of NATO and of America’s security guarantee has bred complacency. What happens in Europe will have profound implications worldwide”, - writes Boris Johnson in his article to The New York Times.