The former Ukrainian president Viktor Yushchenko has urged Europe to unite and wake up to Russia's "medieval policy", after the Salisbury poisoning scandal.
Mr Yushchenko, still visibly scarred from facial welts that developed after a poison attack almost killed him in 2004, in a rare interview recalled his own brush with death.
But he declined to confirm if he thought Russian President Vladimir Putin was to blame.
Speaking to the BBC, Mr Yushchenko said the Kremlin's current policies represented a major threat.
"I would like what we call 'United Europe' to finally realise the biggest challenge for its citizens is the medieval policy that Russia pursues in the 21st century," he said.
"I feel pain for Europe being so blind. That European countries are so unfriendly to each other and have so little solidarity in respect to Russia's policies."
The poisoning in Britain of former intelligence officer Sergei Skripal, 66 and his daughter Yulia, 33, has met with global condemnation of Moscow, thought to be responsible.
Last week, more than 18 EU states, the US and Canada announced the expulsion of more than 150 Russian diplomats in response to the poisoning.
Of the attack on him, Mr Yushchenko recalled the painful effects he experienced ingesting Dioxin, a toxic chemical.
"When I arrived home and kissed my wife the first thing she said was 'your lips taste metallic'," he said.
A subsequent investigation concluded that the poison had been added to rice he ate at a dinner with two Ukrainian security officials.
"On the second or third day, my body started swelling. My head grew in size, dramatically. The pain spread all over the body. And then I started having inflammations and pus forming all over my body."
The attack happened while he was running for the Ukrainian presidency against Viktor Yanukovych, the candidate that Russia was backing.
Asked if he believed Mr Putin had ordered his poisoning, Mr Yushchenko responded: "I have an answer, but I cannot voice it."
While Mr Yushchenko eventually managed to win the election, Mr Yanukovych would later go on to be elected in 2010, eventually being ousted in Ukraine’s revolution of 2014. He now lives in exile in Russia.
The Yushchenko interview came as Russian foreign minister Sergei Lavrov suggested that Britain could have been responsible for the poisoning of the Skripals.
Mr Lavrov told a news briefing: "This could be in the interests of the British government which found itself in an uncomfortable situation having failed to fulfill promises to its electorate about the conditions for Brexit.
"In times of cold war there were some rules, but now Britain and the United States had dropped all propriety and were playing children's games."
_________
Read more
Sixty expelled Russian diplomats arrive back in Moscow
_________
The diplomatic fallout between Russia and Britain continued to deepen over the weekend, as Russia pressed for consular access to Mr Skripal and his daughter. The Russian embassy in London claims it is entitled access to the Russian nationals under normal diplomatic rules, but UK officials have been hesitant to permit access to the Skripals, who remain in a serious condition in hospital. Foreign officials said on Sunday that they were considering Russia's request.
Pressure is also mounting on British business leaders to boycott a major summit in Russia next month. The St Petersburg International Economic Forum is Russia's main annual business meeting. Last year Bob Dudley, BP's chief executive was among the attendees.
Bill Browder, an American fund manager and anti-corruption activist has said it would be wrong for British executives to attend.
"Any self-respecting CEO would be very foolish to send anyone to that forum. Doing business in Russia is... going into business with the mafia," he said, adding that it would be "highly unpatriotic" for UK companies to attend the summit following the Salisbury poisonings.
BP has declined to confirm whether or not Mr Dudley will attend this year's event, which comes just three weeks before the start of the World Cup in Russia.
On Saturday, Russia told Britain that 50 diplomats would have to leave Moscow, meaning another 27, on top of 23 already expelled. The British ambassador in Moscow Laurie Bristow said he was told on Friday that the his country's diplomatic presence would have to be cut to the same size as the official Russian presence in Britain within a month.
On Saturday four German diplomats were expelled from Moscow, as part of a tit-for-tat response to the European expulsion of Russian diplomats.
Russia had said it would retaliate, also labelling the searching of an Aeroflot plane at London's Heathrow Airport on Friday as a "deliberate provocation". British authorities said the checks were routine.