The UK Government today warns a Yes vote would result in the relocation of the entire submarine facility from Her Majesty's Naval Base Clyde – currently Scotland's largest employment site.
Some 6700 military and civilian jobs are at Faslane, and a further 1500 posts are due to be created by 2022.
Labour calculate a further 11,000 people are also directly and indirectly reliant on the base for their livelihoods.
The warning comes in the UK Government's response to a report by the Commons Scottish Affairs Committee on the future of Trident, with ministers stressing the Clyde continues to offer the best location for the missiles.
The Coalition says £3.5 billion has been spent preparing for the new generation of Vanguard submarines and that any replication of facilities south of the Border would cost at least this figure and probably more.
Faslane is not only the home to a fleet of nuclear-armed subs but conventionally armed ones too, as well as minesweepers and training facilities.
Ministers warn: "Since the collocation benefits would be required in any alternative location, there would be no question but that the entirety of the submarine enterprise on the Clyde would be relocated."
The Scottish Government has made clear that if voters chose independence next year, then Britain's nuclear deterrent would be removed from Scotland. This, it has stressed, would be "non-negotiable".
But it also insists Faslane has a "bright future" as the home of an independent Scotland's conventional naval force.
In October, the Scottish Affairs Committee – which does not have SNP representation – accepted in a report that Trident could be "disarmed within days and removed within months".
Yet it pointed out that relocating Britain's nuclear deterrent would cost several billion pounds and would take many years to replicate the safety facilities at Coulport, where the nuclear warheads are kept.
Labour's Ian Davidson, the committee chairman, told The Herald: "Come the referendum, Scotland is now faced with a quite clear choice between 6000 jobs rising to 8000 being based at Faslane or the entire submarine force being removed. The burden of proof now passes to the SNP to explain how they will fill this huge gap."
Jim Murphy, the Shadow Defence Secretary, said: "This would be a fatal blow to Faslane and thousands of jobs throughout the west of Scotland. The Clyde is becoming the UK's submarine centre and emerging as a world leader. This revelation means that if the SNP got their way, not only would there be no Royal Navy shipbuilding on the Clyde, there wouldn't be a single sub based in our waters."
However, Angus Robertson, the SNP leader at Westminster, hit back, insisting Faslane had a "bright future as the base for Scotland's conventional naval forces with independence rather than a repository for Trident nuclear weapons that the people and parliament of Scotland do not want".
He went on: "One of the biggest benefits of an independent Scotland will be the ability to remove Trident from the Clyde. Scottish public opinion and a majority of the members of Scotland's Parliament are strongly opposed to nuclear weapons being based in Scotland and only a Yes vote in 2014 can guarantee Trident's removal.
"Just last month, Defence Minister Philip Dunne made it clear there is enough room at the Devonport Yard on the south coast of England to base Trident.
"The UK Government is content to dump Trident nuclear weapons near Scotland's biggest city, but is unwilling to station them on the south coast of England – for safety reasons. That speaks volumes for Westminster's attitude to Scotland."