The latest salvoes for the Unionist cause are aimed at the uncertainty regarding the defence commitments, specifically naval, of an independent Scotland ("Salmond warned of defence 'disaster'", The Herald, December 31).

There is a serious problem regarding the Unionist predictions, even those made by apparently experienced personnel. The assumption is made that Scotland will continue to operate UK strategies, and will consequently be unable to pay for these. But is this assumption true?

When we examine in detail UK defence strategy we can see that this is based on a post-imperial, post-colonial, global outlook. This requires high cost commitments, in the form of a nuclear submarine fleet, aircraft and assault carriers, with their support units, long-range aircraft, intercontinental missiles and a network of overseas bases capable of supporting all three armed services.

This is the defence strategy to which the Scottish taxpayer contributes at present, but this is not the only way of looking at defence. Most European countries have a different defence model, one based on defending the homeland in the context of the European continent and North Atlantic rather than a complete global strategy. Global action is usually undertaken within United Nations, EU or similar umbrella organisations.

Denmark has a population similar to Scotland, and has defence commitments in the North Atlantic to the Faroe Islands and Greenland. For this, the Danes have a deep-water navy consisting of six frigates and six long-range patrol boats, some of which carry missiles. These ships have all been built in Danish yards and are based in two naval bases, in Fredrickshavn and Korsor.

The UK Royal Navy has 44 major units, 16 of which are directly related to global strategy (nuclear submarines and aircraft/assault carriers). There are only 28 vessels of destroyer or frigate class, and some of these are due to be decommissioned. This represents about five times the size of the comparable Danish navy, yet the UK is a country 12 times the size of Denmark.

So what about defence in an independent Scotland? If the SNP were to advocate a global defence strategy, then Unionist predictions would possibly be correct. If the SNP advocated a defence on the European model, what would be the outcome? Firstly, Scotland's "share" of the 28 suitable vessels would be, at most, three ships – far too small for Scotland's needs. A Scottish navy would have to embark on a shipbuilding programme to construct approximately nine vessels. It is of note that the destroyer HMS Daring took six years from laying the keel to commissioning, so the construction of nine similar ships would ensure sufficient work in the Scottish naval yards for some considerable time.

Scotland has only one base, Rosyth, suitable for purpose. Rather than closing Faslane, as the Unionists predict, it is clear from Danish comparisons that Faslane would have to be redeveloped from a nuclear submarine base to one designed for the Atlantic fleet.

All of this is conjecture, and depends on political decisions. To assume that England will be a benevolent neighbour, sharing shipyards and bases, is not tenable. From the tone of your article, it is clear that much of Westminster, and probably all of Whitehall, would see a Scotland becoming independent as little more than an act of treachery, and will be most reluctant to do anything which will benefit Scotland. The main political decisions have to be taken in Edinburgh. The victory of the SNP in 2011 was due to a political viewpoint which was both visionary and clear thinking, reducing the arguments of opponents to obstructionism and pettiness. If the SNP hope to win an independence referendum, they must adopt similar strategies.

D MacRae,

38 Marchfield Avenue, Paisley.

Amid Lord West's comments about defence industries which have been shrinking rapidly over the past 20 years, I note the even sillier comment from Jim Murphy: "The public deserve to know how we would defend ourselves ... and how many aircraft carriers we would have."

Shouldn't Jim Murphy, as defence spokesperson, tell us what defence does Britain's military give us, given that Scottish taxpayers are paying for it?

We had Russian naval vessels camping in Scottish territorial waters and supposedly discharging waste into the Moray Firth, and where was the Royal Navy monitoring vessel?

In the absence of Nimrods, was there any good quality aerial surveillance? Probably not.

As for aircraft carriers, Britain does not have any effective aircraft carrier until we have completed the construction of the two new aircraft carriers whose main justification seems to be the important jobs they are maintaining at Govan and Rosyth. Even when completed one is going into mothballs, and the other may not have any aircraft on it.

Scotland's territorial and maritime defence would be best served by making Scotland its own aircraft carrier with aircraft based at Lossiemouth and Leuchars and supported by a fleet of fast, efficient modern vessels. At least in the face of a terrorist attack on a west of Shetland oil field, with no Royal Navy or SAS based in Scotland, we would not have to ask Norway to send a vessel to our assistance.

George Leslie,

North Glassock, Fenwick.