Cawdor barracks to shut with 600 troops moving to St Athan
An Army base in Pembrokeshire is to close with 600 troops transferred to another site in the Vale of Glamorgan.
Defence Secretary Philip Hammond announced that 14th Signal Regiment would move from its base at Cawdor - formerly Brawdy - barracks, near St David's, to St Athan after 2018.
The UK government is investing £1.8bn in a new basing plan across the UK with £100m being spent in Wales.
It comes as thousands of troops are expected to return from Germany.
Mr Hammond said the remote Cawdor barracks site was "not fit for purpose - that is the reality".
"It's a very remote, singleton garrison site," he said.
"I think I'm right in saying it has the highest level of unaccompanied service of any Army location in the UK, reflecting the fact that people are reluctant to move their families to a site that remote."
He added: "The physical state of the accommodation was a significant factor."
He explained that housing the Signals regiment at St Athan fitted in with the strategy of regional concentration.
Mr Hammond said the Ministry of Defence (MoD) was working with the Welsh government to maximise the use of St Athan, while the MoD will dispose of the Cawdor site.
The defence secretary said local planning constraints meant it was unlikely to be used for housing, but could return to agricultural or non-developed use.
The changes are part of a new "basing plan" for the Army to follow the return of British troops from Germany.
In another move, the 1st Battalion Welsh Guards will move from Hounslow, west London, to Pirbright in Surrey.
Stephen Crabb, the Wales Office minister with responsibility for defence and Preseli Pembrokeshire MP, said: "Whilst it is disappointing that we will see Cawdor Barracks in Brawdy, Pembrokeshire close, these changes are essential for our future armed forces.
"I am pleased that the defence footprint is largely being maintained and that 14th Signal Regiment will be relocating within Wales to St Athan.
"It is also expected that Wales specifically will receive much-needed infrastructure investment of approximately £100m to support the rebasing."
A Pembrokeshire council spokesman said: "It's a sad day for Pembrokeshire. It's very disappointing news and the council will continue to press the government to overturn the decision."
The authority said there was around 250 permanent Army personnel and their families who lived locally to the barracks.
Thousands of troops are expected to return from Germany during the next few years.
Ministers say it is a good time to review where they are based across the UK.
Troops from the 14th Signal Regiment are experts in electronic warfare.
In October 2010, St Athan lost out when a proposed £14bn defence training academy, which would have created 2,000 jobs in the Vale of Glamorgan, was scrapped.
It was axed as the UK government announced cuts of up to 8% in the defence budget.
Last summer two Royal Welsh battalions were merged under defence cuts.