Theresa May has told Vladimir Putin the Salisbury poisonings have “spectacularly backfired” after 24 countries joined with Britain to “dismantle” Russia’s worldwide spy network.
The Prime Minister vowed never to allow President Putin’s espionage machine to be rebuilt after the US and other Western allies announced the expulsion of more than 130 Russian intelligence officers.
President Donald Trump ordered 60 suspected Russian spies to leave the US - including 12 from the United Nations in New York - while 16 EU countries and five other non-EU members also gave Russians notice to leave in the largest collective expulsion of Russian spies in history. At least two other EU members will follow suit today.
Mrs May said the unprecedented show of solidarity - which outstripped even Downing Street’s expectations after days of intense diplomacy - sent the “strongest signal” to the Kremlin that Russia “cannot continue to flout international law and threaten our security”.
The White House said Mr Putin could no longer be in any doubt that “actions have consequences”.
The international response to the Salisbury attacks, which follows Mrs May’s decision to expel 23 Russian diplomats from London earlier this week, was described by experts as a “heavy blow” to Russian intelligence-gathering.
Donald Tusk, the President of the European Council, said “additional measures” including more expulsions by more countries, could not be excluded in the “coming days and weeks”.
Mrs May said: “President Putin's regime is carrying out acts of aggression against our shared values and interests within our continent and beyond.
“If the Kremlin's goal is to divide and intimidate the Western alliance, then their efforts have spectacularly backfired.”
The expulsions were welcomed by Foreign Secretary Boris Johnson who said on Twitter: "Today's extraordinary international response by our allies stands in history as the largest collective expulsion of Russian intelligence officers ever & will help defend our shared security. Russia cannot break international rules with impunity."
Some 48 diplomats at the Russian embassy in the US have been asked to leave and 12 Russians who work at the United Nations. The Russian consulate in Seattle will also be closed.
Senior US administration officials said the Russians being expelled were intelligence officers who are being "cloaked" by their diplomatic status.
Jeremy Corbyn remained isolated in refusing to directly attribute blame for the poisonings of Sergei and Yulia Skripal to the Kremlin, saying only that Moscow was “directly or indirectly” to blame.
He was also accused by one of his own MPs of lying when he said in a Commons debate yesterday that he had been a “robust critic” of the Russian government for 20 years.
The Labour MP John Woodcock pointed out that after Russia’s annexation of part of Ukraine, Mr Corbyn wrote that the invasion was “not unprovoked”.
Mrs May said police investigating the Salisbury attack had now established that 130 people could potentially have been exposed to the Novichok nerve agent, which had been “stockpiled” by Russia in recent years following work on “delivering nerve agents, probably for assassination”.
The mass expulsion was greeted with fury in Moscow, which said Britain’s allies had “blindly” followed Mrs May’s lead, resulting in “escalating the confrontation”.
Mr Putin's spokesman, Dmitry Peskov, hinted the Kremlin would respond with tit-for-tat expulsions, saying Russia would proceed from the "principle of reciprocity".
Germany, France and Poland will each expel four Russians, with others deported from Lithuania, The Czech Republic, Denmark, Italy, the Netherlands, Spain, Latvia, Romania, Croatia, Hungary and Estonia.
Canada, Norway, Macedonia, Ukraine, Sweden, Finland and Albania will also expel suspected spies, with Belgium and Ireland confirming they will announce expulsions today.
Britain had also been hoping Nato would consider expelling Russian officials, but the plans hit a roadblock when Belgium, which only has a handful of diplomats in Moscow, vetoed the move in case Russia counted Brussels-based Nato staff in any tit-for-tat move against Belgium, which would wipe out its entire Embassy.
Professor Anthony Glees, the director of security and intelligence studies at Buckingham University, said: "It is a heavy blow to the Russia intelligence-gathering. They are more on their own than they have ever been."
Mrs May scored a diplomatic victory at a Brussels summit of EU leaders on Thursday. Heads of state and government criticised the Salisbury attack and agreed it was highly probable Russia was responsible.
The EU recalled its ambassador to Moscow for consultations which was described by Jean-Claude Juncker on Friday as “unprecedented”.
“The European Council condemned in the strongest possible terms the recent attack in Salisbury,” Mr Tusk said at a press conference in Varna, Bulgaria. He is in Bulgaria for EU talks with Turkey.
The action comes after more than a fortnight of mixed messages over America’s willingness to take a tough line on Russia for the Salisbury poisoning.
The White House declined to point the finger at Russia explicitly the day Theresa May linked the Kremlin with the attack during an address in the House of Commons.
Mr Trump also failed to mention that attack during a phone call with Mr Putin last week and at times has not matched critical rhetoric of cabinet colleagues and officials.
Senior US administration officials pushed back on the suggestion they had been sending “mixed messages” on Monday, saying that they stood with Britain over the attack.
A No 10 spokesman said: "We welcome today's actions by our allies, which clearly demonstrate that we all stand shoulder to shoulder in sending the strongest signal to Russia that it cannot continue to flout international law."
Defence Secretary Gavin Williamson, visiting Estonia, also welcomed the expulsions. "I think that is the very best response that we can have because their intention, their aim, is to divide and what we are seeing is the world uniting behind the British stance," he said.
"That in itself is a great victory and that sends an exceptionally powerful message to the Kremlin and President Putin."