Boris Johnson has called Vladimir Putin a “f------ idiot” and told the Russian leader: “No more empire.”

The former prime minister made the comments as he declared that Ukraine and other eastern European countries would never rejoin the “Russian imperium”.

He also warned that the West was in “retreat” and that Donald Trump would not “do everything... to help Ukraine” unless Nato members started spending more on defence.

Mr Johnson told Delfi, a Baltic news website: “What Putin is doing is archaic and barbaric, and he needs to understand that Estonia, Latvia, Lithuania – none of these countries are part of the Russian imperium anymore. And nor is Ukraine.

“It’s over – over, over, over.

“No more empire, Vladimir, you f------ idiot,” he said, adding: “Excuse my language.”