just what kind of army does Scotland need? Scots wondering how to vote in the independence referendum have cause to feel confused and a little fed up with what they've been hearing from both sides of the independence debate. Neither is making sense on defence.

First, we had the SNP yesterday attacking the UK Defence Secretary, Phillip Hammond, for cutting back on the numbers of British troops being brought back to Scotland from Germany. His predecessor, Liam Fox, had promised nearly 6000 extra troops to be stationed in Scotland by 2020, and it turns out there are only to be around 600. Betrayal. Oor British so'jers, taken frae us.

However, it is a little odd, surely, for the SNP to be complaining about British troop strength in 2020 when Scotland would, if it has its way, be independent and the British army wouldn't be here at all. It reminds me of that joke about the Morningside ladies in the restaurant. One says: "Isn't the food here terrible?" The other replies: "Yes, and look how small the portions are."

Equally, the UK Government is all over the place on defence, and seems determined to do the SNP's job for it. One day it's saying that the military is the glue that keeps the Union together, and accusing the SNP of risking military jobs through independence. Then the very next day it says it's going to send all the jobs down to Salisbury Plain or wherever.

I'm sure the Government wouldn't do something so crude as replant armed forces to shore up Conservative electoral support in the south of England. However, you can't help feeling that the Tories have rather lost interest in Scotland now that they are such a marginal political force here. It was Liam Fox who promised the Scottish Six Thousand, and he of course is a Scot. We'd been led to believe that more soldiers would come here to compensate for the closing of Scottish bases in the Strategic Defence Review.

However, Mr Hammond is right in one historical sense. The armed forces were part of the Union glue, one of the key institutions that kept the United Kingdom together in days when the Scottish regiments fought Britain's wars. From Waterloo to the First World War it was the Scots who provided the sharp end of the British Empire. The Highland regiments in particular were used as attack forces because they were so fierce and didn't seem to care very much about dying. As late as the First World War Scots took far greater casualties than the English because they always tended to be in the front line.

Scotland's identity in the Victorian age was heavily bound up with its military prowess in episodes like the Thin Red Line at Balaclava, which was actually tartan: the 93 Highland Regiment. Scots prided themselves on their military valour and Scottish soldiers were folk heroes. Working-class Scots were linked to the UK through the Scottish regimental "families". Scotland's investment in Britain had a lot to do with the blood Scots shed for Britain.

That's all over now, however. Most of the Scottish regiments have passed into history, along with the Ladies from Hell, and the British army doesn't need shock troops any more. Modern warfare is highly technical and the Highland charge isn't much use in the age of cyber warfare. The forces that are being brought back from Germany are a consequence of the peace dividend, which is what this latest row is about.

So, what would the SNP's Scottish defence force look like? Surprise, surprise, it looks rather like it looks now – sans Trident. The UK defence review left Scotland with one mobile brigade, one naval base and one aircraft base, which just happens to be what Alex Salmond says the Scottish defence force would need. How convenient. However, these bases couldn't just be taken over as they are now, because they are part of the integrated UK armed forces. All the weapons, aircraft, transport, logistics, command structure would be controlled by England, which would never do. Scotland would have to start from scratch.

This may not be such a daft idea. Professor Malcolm Chalmers of the Royal United Services Institute – the British army think tank – says it would be quite possible for Scotland to have a rather good little defence force by 2030 to deal with terrorism, fisheries protection, guarding the oil and even participating in peace-keeping operations abroad. And it could do this for about £2.2 billion, which is less than the £3.2 billion we contribute at present. In other words, we'd have a Nordic-style army and still have change.

However, this isn't quite what the SNP has in mind. After its landmark decision to remain in Nato after independence, Scotland may end up so closely integrated with the British Army that it will be hard to tell the difference. If Scotland is a succession state, as the SNP wishes, then both the new entities would be pledged to co-operation on maintaining Nato's forward defence, of which at least two of Scotland's bases are key elements – Lossiemouth and Faslane. The two armed forces will be working so closely together, you might even call it a military union.

And why not, when the SNP has already proposed a social union, a monetary union and a monarchical union? There is of course the small question of Trident. The SNP says it will be removed even after Scotland joins Nato. But since it is part of Nato's "strategic guarantee" it is inconceivable that Scotland would remove it overnight. As part of the deal to be in Nato it would have to be phased out. Under the new SNP defence policy, as Prof Chalmers says, Trident will be here for "decades rather than years".

So, to sum up: Scotland will have to accept Trident for the time being because it is central to Nato. Scotland will work with the British Army because of Nato, and we will have the same military bases and personnel that we have now. Just as in the days of Empire, Scots will still be fighting Britain's wars. Which begs the question: why bother with independence?