The Prime Minister has admitted that hard-hitting financial sanctions may not be enough to prevent Russian president Vladimir Putin from signing off an invasion of Ukraine.
Boris Johnson warned that a Russian incursion across the border into Ukraine “could be the biggest war in Europe” since the Second World War, with casualties on both sides.
The British leader, in comments made while at the Munich Security Conference on Saturday, said it appeared Moscow’s plan for an offensive had “already in some senses begun”, pointing to the escalation of violence in Russian-backed separatist-held areas in eastern Ukraine.
The UK has pledged support for Kyiv through armed forces training and by sending anti-tank weapons, but Mr Johnson said, given Ukraine is not a Nato member, sanctions would be the main focus in terms of hurting Russia in the event of an invasion.
He admitted that even a joint venture by Britain and the US to prevent Russian state-linked firms from trading in pounds and dollars – a move he predicted would hit the Kremlin “very hard” – may “not be enough on its own”.
He told the BBC’s Sunday Morning programme: “We have to accept at the moment that Vladimir Putin is possibly thinking illogically about this and doesn’t see the disaster ahead.”
Western fears about an invasion have become more pronounced in the past week, with US President Joe Biden stating on Friday he is “convinced” Mr Putin is preparing to order troops into Ukraine within days.
Mr Johnson appeared to back that conclusion, telling the BBC that is what the “evidence points to”.
With Ukraine surrounded on three sides by about 150,000 Russian soldiers, warplanes and equipment, the Prime Minister predicted a “bloody and protracted conflict” and called on his Russian counterpart to “engage in serious diplomatic conversation” to prevent a “sheer cost in human life”.
Concerns about an attack have been fuelled by rising violence in rebel-held areas of the country, with Ukraine’s military announcing that two soldiers died on Saturday as violence escalated in the east of the country between government forces and separatists – a conflict which has been going on since 2014 and seen some 14,000 people killed.
Hundreds of artillery shells have exploded along the contact line between the two sides, and thousands of people evacuated from eastern Ukraine into Russia in a move some commentators believe is designed to paint Kyiv as the aggressor.
There is anxiety that Russia, which has been carrying out military exercises across the weekend, including nuclear drills, could use the increase in tension in the separatist-held regions of Donetsk and Luhansk as a pretext for an attack.
The Prime Minister said: “The fact is that all the signs are that the plan has already in some senses begun.
“That’s what our American friends think and you’re seeing these provocations now in Donbas – these explosions and so on – that we’ve been warning about for a long time.
“The plan that we’re seeing is for something that could be the biggest war in Europe since 1945 just in terms of sheer scale.”
Foreign Secretary Liz Truss also appeared to raise the stakes as she claimed Mr Putin “will not stop at Ukraine”, arguing he is looking to piece the Soviet Union back together.
Speaking to the Mail On Sunday, the Cabinet minister said the West needs to “stop” Moscow in its tracks or else the Russian leader will look to “turn the clock back” by possibly annexing the Baltic states – such as Estonia and Latvia – and the Western Balkans, which includes Serbia and Albania.
One of her department ministers, James Cleverly, said he believed the US had “very credible intelligence” to suggest as many as five million people could be displaced and pushed into western Europe if Moscow and Kyiv lock horns.
The Minister for Europe told Times Radio that Ukrainians “are ready to stand and fight”, adding: “It will inevitably lead to a movement of people through a refugee move across into other parts of Europe, westwards into other parts of Europe.”
Mr Putin and Alexander Lukashenko, the Belarus president and Moscow ally, spent Saturday watching Russian forces flex their military might during massive nuclear drills, which involved multiple practice missile launches.
Belarus has since announced that the two countries will extend joint military exercises, which had been due to end on Sunday, in a move that is likely to create further unease.
It is feared the displays are a further indication that Russia, which also conducting naval drills off the coast of the Black Sea, is gearing up for an offensive.
But a Russian diplomat said “our drills on our territory should not worry anyone”, and accused the West of creating an “artificial crisis” in Ukraine.
Dmitry Polyanskiy, the first deputy permanent representative of Russia to the United Nations, was asked on Sky News’ Trevor Phillips On Sunday programme whether Mr Putin is “enjoying” the international spotlight.
He replied: “I think that ‘enjoying’ is not the right word that you can use in these circumstances when we can see absolutely the lack of responsibility on behalf of Western leaders right now, and a lot of scaremongering and warmongering.
“I don’t know anybody who is enjoying this situation in Russia.”