Ukraine is currently surrounded on three sides by about 150,000 Russian soldiers, warplanes, and equipment, with the West predicting that Moscow is poised to launch an offensive on Kiev – a battle Mr Johnson has predicted would be “bloody and protracted”. Professor Michael Clarke has warned Russia could launch a full-scale invasion on Kiev by blacking out its cyber networks within a day before moving troops in the following 24 hours. Speaking to BBC Radio 4 Today programme, he said: “The Russians have got complete dominance by land but also very importantly, by air, sea, and cyberspace.
“Putin has a vice around Ukraine and he could snap it shut, some or all of it, if he decides to.
“If he goes for broke and it really would be a very big step and tries to conquer Ukraine then we would expect to see a push West from Donbas and linking up with troops in Crimea to establish a land corridor between the Donbas region and Crimea.
“It is likely it will be simultaneous with an invasion of Kiev.
“The point is having such dominance in the air, the Ukrainians have an airforce of about 120 aircraft.
“The Russians have moved double that into the area and they more or less control cyberspace.
“They would be able to blackout quite a lot of what is happening on the ground and make it very difficult for the Ukrainian army to operate.
“One would expect a build-up of cyber-attacks followed by an air campaign with a lot of long-range artillery and rocket artillery attacking specific centres.
“Then after 24 hours of that troops will be seen moving in and the Ukrainian army would be effectively immobilised by Russian action.”
President Putin must “step back from his current threats” as part of any solution to the Ukraine crisis, Boris Johnson has said, following suggestions the Russian leader is open to last-ditch peace talks.
The Prime Minister said it is a “welcome sign” that a phone call between French leader Emmanuel Macron and the Russian president had shown Mr Putin may be “willing to engage in finding a diplomatic solution”.
Downing Street said the Prime Minister and Mr Macron agreed during a discussion on Sunday that the next week would be “crucial” in the bid to prevent an invasion of Ukraine.
It comes as the White House said US President Joe Biden has “accepted in principle” a meeting with Mr Putin as long as Russia holds off on any invasion plans.