However, The Herald has been told the Ministry of Defence has asked BAE not to close the Ports-mouth yard completely, but to mothball the site in case Scots vote yes in the 2014 independence referendum.
This suggests that, rather than maintaining it has no contingency plans if Scotland votes for independence, the MoD is considering the possibility. It also suggests that a "yes" vote could lead to a future UK Government deciding to place its warship orders in England rather than in Scotland.
Already, council leaders in Portsmouth have warned that the possibility of Scottish independence should lead the UK Government to lobby BAE to save the English yard.
Expectations are high that BAE will announce its decision on the future of its shipyards early in the new year. It has been reviewing operations across its facilities on the Clyde – at Govan and Scotstoun – as well as at Portsmouth, looking at rationalising its operations in light of future defence orders.
In November, Nigel Whitehead, the company's chief executive, said plans for a reduction in footprint could see the cessation of manufacturing at one of the sites.
At present, Britain's shipyards are working on the Royal Navy's two new aircraft carriers, but the workload begins to run down sharply after 2015.
The assumption is that from 2020 the UK will each year make only one major warship – the Type 26 Global Combat Ship – and develop a new ship design every six years. Such a workload would not sustain three shipyards in their present form.
Last week, Philip Dunne, the Coalition's military procurement minister, refused to be drawn on which yard would get the Type 26 work or say precisely when it would begin, but noted how the UK Government – other than in times of world wars – had never placed a warship order outside the UK.
In contrast, Vice-Admiral Andrew Mathews, Chief of Materiel Fleet, said building the Type 26 frigates on the Clyde in an independent Scotland was "one of the options open to us".
Jane's Defence Weekly says Portsmouth is seen to be most at risk in the BAE review.
Information supplied by defence consultants is believed to have confirmed to BAE that keeping its three yards open is uneconomic while a separate Whitehall report to Philip Hammond, the Defence Secretary, has suggested Portsmouth as the most likely shipbuilding operation to be axed.
Last night, Labour's Thomas Docherty, who is a member of the House of Commons Defence Committee, welcomed further signs the Scottish yards would be saved albeit at the expense of Portsmouth and the loss of up to 1500 jobs.
"If this leak is true, then this will be a great relief to the Scottish yards involved," said the Fife MP, who pointed out how the flexibility of the Scottish workforce to be able to work at either of the Clyde yards had helped their case for survival.
However, one worry is that if BAE axes shipbuilding at Ports-mouth, it could compensate this by boosting refurbishment operations there, which could have a detrimental effect on similar work undertaken at Rosyth on the Firth of Forth.