After almost two years of uncertainty and speculation over the base in Fife, which the RAF is due to leave by 2015, Defence Secretary Philip Hammond is due to announce that it will be replaced with a “significant” army presence.
The base will also receive £60 million of investment from a total of £1.8 billion being ploughed into upgrading sites across the country.
The new army presence is expected to be one of the units pulled out of Germany in the major reorganisation and may be the Highlanders infantry battalion.
The revelation comes amid a row over the government’s decision to renegue on a promise to double the size of the army in Scotland to between 6,500 and 7,000 by 2020. Instead it will be confirmed tomorrow that there will be a “modest increase” of 20 per cent, taking it to about 3,800.
SNP Deputy First Minister Nicola Sturgeon last night published a letter to Mr Hammond demanding clarification on the plans and the future of other bases.
Already it is expected that, as revealed in The Scotsman last year, plans for a new super-base at Kirknewton, near Edinburgh, have been dropped, while proposals to use HMS Caledonia in Fife as an army base are also in doubt, as is the future of the Arbroath base when the Royal Marines leave in 2016.
However, a source close to Mr Hammond said the announcement would be good news for Scotland, with investment in basing north of the Border and an increase in army numbers at a time when the total is dropping from 100,000 regulars to 80,000.
The Leuchars announcement means its uncertainty is at least put to rest. Since the last basing announcement in 2011, when it was said the RAF would be pulled out, there had been speculation that despite promises on an army unit going there it might be closed altogether.
There had also been talk of the army headquarters in Scotland being moved to Leuchars, but this seemed to be quashed when it emerged that current HQ Craigiehall, in Edinburgh, would not be closed and sold.
However, North East Fife Lib Dem MP Sir Menzies Campbell had been lobbying hard to get the RAF to stay at Leuchars instead of being transferred to Lossiemouth in Moray. It is thought the runway will be maintained and Leuchars kept as a back-up base.
A senior defence source said: “The new basing plan brings certainty and security to our armed forces and to Scotland.”
He said the firm commitments and plans unveiled tomorrow will be in stark contrast to a lack of plans from the SNP.
He said: “People should judge the SNP’s credibility on defence against its own proposals for investment in Scotland’s defence. They propose an annual defence and security budget (£2.5bn) that is a 14th of what the UK spends on defence alone (about £33.5bn), for a country with a tax base of one 12th the size.”
The SNP said the announcement would show the UK government could not be trusted on its commitments to Scotland.
In her letter to Mr Hammond, Ms Sturgeon pointed out that his predecessor, Liam Fox, had promised in 2011 an increase of between 5,000 and 7,500, although this was later clarified by the MoD to mean the total army size was due to be up to 7,000.
Ms Sturgeon said: “Scotland has already been disproportionately affected by the defence cuts, and we now hear any increase may be limited to only a few hundred army personnel.”