While it might sound far-fetched, the "fact-based prediction" is the basis for his new book War With Russia, which is a fictional account of how a nuclear war in the continent could unfold. Billed as an "urgent warning from senior military command" it's designed as a "wake-up call" to military and political elites who could be sleepwalking into a nuclear disaster, General Shirreff claims.
"Add the other chilling aspect of this, that nuclear weapons are hardwired into Russian defence thinking, then it gets really serious and potentially existential," he said.
"Because if there is any hint of a Russian military foot stepping across those borders of Latvia, Estonia or Lithuania that means war under article five of the NATO treaty ... but it also means nuclear war in Europe.
"I pray that it does not happen but I have this awful sense of drift towards this ghastly potential result," he told reporters in London on Wednesday.
It's a bold comment from the retired general who served in Europe from 2011-2014 and made headlines for referring to David Cameron as a "diplomatic irrelevance" during the Ukraine crisis.
The book comes with the endorsement of former Supreme Allied commander Europe Admiral James Stavridis who deems Russian aggression a greater threat than terrorism.
It also includes the warning that NATO need to step up their defence systems if it is to provide enough of a deterrent to Putin who he describes as an "adventurous" leader proven capable of disregarding international law and seizing situations to his advantage.
"We should never assume rationality in strategic affairs, the human dimension is critical here and history is full of examples of irrational decisions being taken by leaders who believe they can get away with it," General Shirreff said.
"What we've seen is an adventurer, an opportunist who's able to make decisions very quickly to seize opportunities as they're presented," he said in reference to the annexation of Crimea which was described as a "copybook" military play.
The warning comes ahead of a NATO summit in July which will see heads of state gather in Poland and five weeks out from a critical referendum on the future of Britain in the European Union which has been couched in security terms.
Asked whether the comments could be seen as inflammatory, General Shirreff said there was nothing provocative about "locking your doors" and was unequivocal about the security risks for Europe if Britain does vote to leave the EU on June 23.
"British security depends on a strong EU. Britain leaving the EU, makes the EU weaker" he said.
"There is a real concern among our EU partners that if you pull a foundation brick out of a wall it begins to make the wall rather more precarious so a weaker EU makes Britain, in turn, less secure."
The major caveat on his dire prediction is that NATO could set the bar "sufficiently high" to provide a deterrent by building up a "credible" land, sea and air force in the Baltics in order to deter the Russian leader who "despises weakness".
"It doesn't take the brains of an archbishop to work out If you can fly in 50 minutes from an air landing division base to Riga you can get a probably get a brigade on the ground in several hours and if you haven't got anything to stop it ... it's a no brainer, you can't deter," he said, adding that Baltic nations are essentially undefended but for their own forces.
"They will fight and they will do their best to defend but it will be almost impossible for NATO to do anything and that's the point of the book; defend forward, put something in place that is credible and capable and deters, then this grim scenario doesn't happen. Because once it's happened, NATO would have one hell of a task to recapture the Baltic States."
NATO and the Russian Presidential Press Office have been contacted for comment.
