BAE Systems has announced it will cut 1,775 jobs at its yards in Scotland and England and end shipbuilding altogether at Portsmouth.
Unitenational officer for shipbuilding Ian Waddell said:
“It is a huge blow to Britain’s manufacturing and industrial base, with many highly skilled workers faced with losing their jobs.
“We will have to examine the BAE business case in detail to see how we can secure a future for the workforces at both Portsmouth and in Scotland. We believe that, if this is approached in a constructive and innovative way, it can be achieved.
“The seeds for this situation were sown in the 1980’s when the Thatcher government used European structural funds to close shipyards, rather than funding investment that would have allowed Britain to compete in the global marketplace for shipbuilding orders against the likes of South Korea.”
BAE's decision was prompted by the decline in work for the Royal Navy’s two new aircraft carriers as construction nears completion by BAE, Babcock, Rolls Royce and Thales.
A statement released by BAE Systems said: "Under these proposals, shipbuilding operations at Portsmouth will cease in the second half of 2014.
"Subject to consultation, Lower Block 05 and Upper Blocks 07 and 14 of the second Queen Elizabeth Class Aircraft Carrier will be allocated to Glasgow.
"The company remains committed to continued investment in the Portsmouth area as the centre of its Maritime Services and high-end naval equipment and combat systems business.
"The company proposes to consolidate its shipbuilding operations in Glasgow with investments in facilities to create a world-class capability, positioning it to deliver an affordable Type 26 programme for the Royal Navy."
The job losses were raised at Prime Minister's Questions today.
David Cameron said his thoughts were with the workers affected by these "extremely difficult decisions".
He added: "We will go on building warships on the Clyde, we will be announcing three new offshore patrol vessels, keeping that yard busy rather than paying for it to remain idle as the last government proposed.
"In Portsmouth, yes there will be job reductions, but there are many more people involved in ship servicing than in ship building, so the workforce will go from 12,000 to 11,000."