Russia has not been so hostile to the UK and the West since the end of the Cold War, Boris Johnson has said, as he prepares to meet his counterpart in Moscow.
In an interview with the Sunday Times, the Foreign Secretary accused Russia of destabilising the West through invasions, killings and attempts to interfere in western elections.
He described the falling out as a "tragedy", and said his hopes at the end of the Cold War that relations might improve now seemed like a "total illusion".
He told the paper: "Russia has not been so hostile to the UK or to western interests since the end of the Cold War.
"In the Crimea, capturing a part of sovereign European territory from someone else's country and holding it for the first time since 1945. Add their destabilising activities in the western Balkans.
"We literally have Russian fingerprints on an assassination attempt in Montenegro. Look at what they're doing with cyber-warfare, with attempted disruption of democratic processes in the UK."
Although Mr Johnson said he had seen "no evidence" that Russian interference had affected the outcome of the EU referendum, he said he had seen evidence of Russian "trolling on Facebook".
It is not the first time Mr Johnson has spoken out against Russia, having previously accused the nation of behaving "as though there is indeed a new Cold War" during a speech in the House of Commons.
He has also attacked them for shutting down investigations into chemical weapons attacks in Syria.
According to the Times, the Foreign Secretary will visit Russia on Thursday to hold talks with his opposite number, Sergey Lavrov.
Despite the strained relationship, he has vowed to find a way to engage with the nation, adding Britain needed to "collaborate" with Russia in order to defeat Islamist terrorism.
He told the paper he would be "pushing very hard to understand" how the Russians view "the endgame" in Syria.
Announcing his Moscow visit in October, Mr Johnson said differences between the countries made it all the more important for them to talk to one another, for the sake of national and international security.