The UK's shared defence forces provide the "security and peace of mind" which underpin almost every area of the debate on Scottish independence, Defence Secretary Philip Hammond has said.
A Yes vote in September would also result in "long and protracted negotiations" over defence issues such as the Trident nuclear weapons at Faslane, according to Mr Hammond.
His latest intervention follows the publication of the UK Government's Defence Analysis Paper, and comments from firms working in the sector.
Speaking at electronics company Thales Optronics in Glasgow, the Defence Secretary is expected to outline his arguments for Scotland remaining in the UK, touching on issues such as Trident and the Scottish Government's proposals for a currency union.
He will say that d efence "provides the security and the peace of mind that underpins almost every single other area of this debate".
He will add: "What we have is precious ... It is our shared history, our common values and our unity of purpose which makes us what we are today. It is Scotland which makes the UK united, and adds the Great to Great Britain.
"Drawn from the four corners of these islands, nothing epitomises more the strength we derive from being a United Kingdom than the men and women in our Navy, Army and Air Force, coming together with a common purpose, to keep our country and our people safe and secure."
Mr Hammond will say that a formal currency union between Scotland and the rest of the UK is " not an item up for negotiation".
On Trident, he will say: "He (Scotland's First Minister Alex Salmond) also wants to dictate the timescales for removing our nuclear deterrent within the first term of Parliament following independence.
"But Alex Salmond knows, as I know, that the future of our naval base at Faslane would be just one of many defence issues that would be the subject of long and protracted negotiations if there were to be a Yes vote in the referendum.
"Because if they insist that it has to go, there would have to be complex talks about the costs and timescales involved. Any notion that it would be quick and easy is just plain wrong."
Mr Hammond's speech comes the day after Ian Walker, the head of engineering firm Walker Precision Engineering, said independence would mean ''dreadful uncertainty'' for its contracts and jobs.
The company employs around 150 people in Glasgow's Tollcross area. Much of its workload comes from the MoD, producing components for the p roduction of submarines, helicopters and tanks.
Last month, BAE Systems has said a continued union between Scotland and the rest of the UK offers "greater certainty and stability" for its business.
Meanwhile, Admiral Sir Mark Stanhope, former first sea lord and chief of naval staff, has sent a letter to Mr Salmond co-signed by former heads of the A rmy, Navy, Air Force and intelligence warning that the SNP's proposed constitutional ban on nuclear weapons ''would be unacceptable for Nato''.
The letter also says proposals to remove Trident "would cause huge practical problems and upheaval for the Royal Navy and require massive additional expenditure".
SNP Westminster leader and defence spokesman Angus Robertson said Mr Hammond was " coming to spread the usual myths and misinformation from the No campaign - for example, he says that you can't have a currency union without a fiscal and political union, which will come as news to France, Germany, the Netherlands and Austria, who all share a currency and are all independent countries".
He added: "Mr Hammond should be using his speech to apologise for Westminster's broken defence promises to Scotland, and UK Government secrecy over radiation leaks at HMS Vulcan at Dounreay.
"Westminster is responsible for a multibillion-pound defence underspend in Scotland, with the loss of more than 11,000 jobs in the last decade. And it is Philip Hammond's Government that callously handed redundancy notices to thousands of serving forces personnel.
"Under Westminster, Scotland has nuclear weapons that we don't need or want but not the naval vessels and marine defences that a nation with our size of coastline and strategic position should have."