The money will fund the creation of 700 accommodation spaces at the base, which houses the UK’s submarine-based Trident nuclear weapons system.
UK defence minister Dr Andrew Murrison said: “This is a big vote of confidence in Faslane and the future of British armed forces there.”
The SNP government has pledged to remove Trident from the Clyde if Scotland votes for independence, but has been warned this could derail its hopes of joining the Nato international defence alliance.
Dr Murrison said: “This new funding is a clear and visible sign of our commitment to Scotland and its continued vital role in the defence of the UK.
“The total number of armed forces personnel in Scotland is increasing and I want to ensure that they get the best possible accommodation and facilities.
“These substantial investments could not be guaranteed under an independent Scotland, so it is clear we are safer and more secure together as a United Kingdom.”
Officials from the Scottish Government met with Nato chiefs earlier this month, but were warned that it is unlikely to gain entry if it is still embroiled in a dispute with an alliance member over military or territorial issues.
“This was seen as a reference to Trident, which is a central component of Nato’s defence make-up, but could be jeopardised if the UK is forced to remove it swiftly from Faslane, with concerns there is nowhere in England which could easily house the submarines.
“The representatives of the Scottish Government came away very disappointed with what they had been told and somewhat ashamed of the false assumptions they seem to have been making,” Dr Murrison added.
“Some rethinking is necessary by the Scottish Government on the way it presumes on supranational organisations like Nato and the EU, and the automaticity or otherwise of an independent Scotland’s membership of them.
“Part of the problem for the SNP case at the moment for membership of Nato is, of course, that the nuclear deterrent is part of Nato’s strategic concept and it’s impossible, I think, for the Scottish Government to argue that an independent Scotland should join Nato if it is not prepared to sign up to the rules.”
The UK government is poised to endorse Trident’s replacement, which would still be placed at the Clyde. Dr Murrison said that Scots are becoming “more and more convinced” of the case for a replacement amid growing global instability.
The SNP has pledge to retain Faslane as the HQ of its new Scottish defence force. It is currently the largest employment site in Scotland supporting 6,700 military and civilian jobs, increasing to 8,200 by 2022.
A Scottish Government spokesman said it will have a strong future as a conventional naval facility if Scotland became independent. He added: “A recent poll carried out in Scotland found that 80 per cent of all those who expressed a view on the question opposed Trident replacement.
“An independent Scotland’s continued membership of Nato will be in the strategic interests of our neighbours and partners, including the rest of the UK, and we made that point at the recent positive and constructive meeting held with Nato at the alliance’s Brussels headquarters.
“We have made it clear that continued membership is contingent on the removal of nuclear weapons from Scotland, and if the people vote for independence they will have voted to support a proposition that calls for the removal of Trident.”