Theresa May has accused Russia of meddling in international elections and spreading fake news.

The Prime Minister used a speech at the Lord Mayor's Banquet to hit out at Moscow as it sought to "sow discord in the West and undermine our institutions".

But she also stressed for the need to engage with Russia to avoid a return to the Cold War.

Addressing the Lord Mayor's Banquet at the City of London's Guildhall, Mrs May said: "As I said in my speech in Florence, the UK will remain unconditionally committed to maintaining Europe's security.

"And the comprehensive new economic partnership we seek will underpin our shared commitment to open economies and free societies in the face of those who seek to undermine them.

"Chief among those today, of course, is Russia."

"Russia's illegal annexation of Crimea was the first time since the Second World War that one sovereign nation has forcibly taken territory from another in Europe.

"Since then, Russia has fomented conflict in the Donbas, repeatedly violated the national airspace of several European countries, and mounted a sustained campaign of cyber espionage and disruption.

"This has included meddling in elections, and hacking the Danish Ministry of Defence and the Bundestag, among many others.

"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.

"So 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 evoked the hope that greeted the fall of the Soviet Union, saying Britain and Russia should not be "in a state of perpetual confrontation", and that Foreign Secretary Boris Johnson will visit Moscow in the coming months for talks.

"We will take the necessary actions to counter Russian activity," the PM will say.

"But this is not where we want to be - and not the relationship with Russia we want.

"We do not want to return to the Cold War, or to be in a state of perpetual confrontation.

"So whilst we must beware, we also want to engage - which is why in the coming months the Foreign Secretary will be visiting Moscow.

"For there is another way.

"Many of us here looked at a post-Soviet Russia with hope.

"Because we know that a strong and prosperous Russia which plays by the rules would be in the interests of the United Kingdom, Europe and the world.

"As a permanent member of the UN Security Council, Russia has the reach and the responsibility to play a vital role in promoting international stability."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."