Just as the government did in the lead up to The Scottish Referendum in 2014, it appears David Cameron is already unleashing resorting to the so-called Project Fear. As The Telegraph reports, following Boris Johnson's lack of acquiescence to Cameron's call for no Brexit, more than a dozen of the country's most senior military leaders will argue that Britain should vote to stay in the European Union because of its importance to national security.
The Daily Telegraph understands that Downing Street is organising a letter stating the importance of the EU to Britain's national security to combat the growing threat of Isil and increasing Russian aggression.
Those likely to sign the letter include Admiral Lord Boyce, General Lord Stirrup and Field Marshal Lord Bramall, three former Chiefs of the Defence Staff, and General Sir Peter Wall, a former Chief of General Staff.
Lord Stirrup told The Daily Telegraph: "I don't carry a torch for the European Union at all but one has to look at the realistic alternative not just the World as we wish it to be. In light of the current threats like Isil, Russia and other threats that might emerge you have to think about how we secure our society."
Lord Bramall said: "I have always felt that a strong Europe in political terms is infinitely stronger if it has Britain inside it.
"If Britain left it would be a much weaker Europe and therefore it would affect the whole balance of power and equilibrium in the Western World.
"That affects not just security, but the political side. The negotiations. It is important to have a match for the various power blocs - China, Russia - it's complementary to Nato. I am sure America would very much want us to be in."
However several other former military chiefs are struggling to reach a decision because they are weighing their concerns about national security against their instinctive euroscepticism.
General Sir Mike Jackson, a former head of the army, is among those who are undecided about whether to sign the letter.
He said: "Yes there is a security dimension to the EU but in my mind it is more of a policing and judicial matter rather than a military matter. The military dimension is provided by Nato."
The letter is likely to be published this week and comes as both David Cameron and Michael Fallon put Britain's national security at the heart of their arguments for remaining in the European Union.
However it is likely to lead to accusations from eurosceptic campaigners that the Prime Minister is resorting to "Project Fear" to make the case for staying in the European Union.
Michael Fallon, the Defence Secretary, said in an article for The Sunday Telegraph that Vladimir Putin, the Russian President, wants Britain to leave the European Union.
He said: "It is not scaremongering to ask which result Putin would favour. If we left, the European Union for the first time in its history would be smaller and weaker. That's obviously in Russia's interests."
The challenges of Russian aggression and international terrorism are global and transnational and Britain "cannot afford" to be alone, he said.
So be afraid Brits, without the help of your Brussels-led 'comrades' you are a defenseless, weak island nation facing the threat alone of ISIS and Russia. We sure have come a long way from "we'll fight them on the beaches..."