The decision to sell off dozens of Ministry of Defence sites has been condemned as "brutal" amid warnings it could put thousands of jobs in doubt.
Defence Secretary Sir Michael Fallon announced 56 more sites would be disposed of by 2040, taking the total number of bases and facilities being sold off to 91.
Ministers have acknowledged there is a risk that having the military concentrated in fewer bases could risk breaking the links between the armed forces and the civilian population, while there was anger from the Scottish Government at the scale of reduction north of the border.
The historic sites of Fort George in Scotland and Brecon Barracks in Wales are among the sites due to be disposed of by the Government, under a review of its estate.
Sir Michael said the estate is too big and costly to run, and releasing the land could enable the building of up to 55,000 new homes.
But the SNP warned the closure of eight sites north of the border risked "savaging" Scotland's defence presence.
Three sites will also be sold in Wales and Northern Ireland, with more than 32,000 acres of land due to be released across the country.
The Ministry of Defence (MoD) estate currently covers nearly 2% of the UK's land area.
Sir Michael told MPs it costs £2.5 billion a year to maintain, and 40% of the MoD's built assets are more than 50 years old.
It is hoped selling the sites could save £140 million of running costs over the next decade.
But Scotland's Deputy First Minister John Swinney said: "These brutal cuts spell the near total removal of the Army from large parts of Scotland and the end of the Royal Navy's presence in Fife.
"It is deeply distressing to witness the announcement to close truly historic sites, such as Glencorse, home to the Army for almost 150 years, and Fort George, a garrison for almost 250 years."
Unions warned that the closures could result in thousands of jobs being put at risk.
Public and Commercial Services union general secretary Mark Serwotka said: "We are opposed to these closure plans that throw the future into doubt for thousands of staff."
Unite national officer Mike McCartney said: "In many instances the bases earmarked for closure are at the heart of their local communities, providing a source of decent and secure employment.
"Their closure will be a severe blow to the local economies where they are located and the people whose livelihoods depend on them."
Defence minister Earl Howe acknowledged that the closures could increase the disconnection between the armed forces and the public.
"The more you concentrate personnel in fewer centres the more that the population as a whole will feel disconnected from the armed services," he said.
"Ways must be found therefore to prevent that happening."