In her most strident criticism of Russia yet, Theresa May has said that Moscow meddles in elections and is guilty of propagating fake news stories to harm the west.
In the prime minister's annual speech in London's Guildhall, May said Russia liked to "weaponise information" as it sought to sow division in the west.
"I have a very simple message for Russia. We know what you are doing and you will not succeed. Because you underestimate the resilience of our democracies, the enduring attraction of free and open societies, and the commitment of western nations to the alliances that bind us.
"The UK will do what is necessary to protect ourselves, and work with our allies to do likewise," she said.
She described how after Russia illegally annexed Crimea from Ukraine, it had destabilised the Donbass in eastern Ukraine, violated the airspace of European countries and engaged in cyber espionage which including hacking the governments of Denmark and Germany,
"It is seeking to weaponise information. Deploying its state-run media organisations to plant fake stories and photo-shopped images in an attempt to sow discord in the west and undermine our institutions," she said.
Moscow is accused of running "troll factories" that push fake news on social media. It emerged that a Russian bot account shared a viral image claiming a Muslim woman ignored victims of the Westminster terror attack as she walked across the bridge.
May told the banquet the UK would increase its military and economic support for Ukraine and would work with Nato to counter the threat from Russia. She also added that the UK would try to stop the "profits of corruption" flowing from Russia into the country.
"Russia can, and I hope one day will, choose this different path. But for as long as Russia does not, we will act together to protect our interests and the international order on which they depend," she told the audience on Monday night (13 November).