On behalf of over 500 members in the maritime mapping organisation, Prospect negotiator Philippa Childs said: "The scale of the cuts has come as a bombshell to our members because it equates to a quarter of UKHO’s total staff.

"Our members understand and support the need for the organisation to move forward and develop its digital products and processes. However, they have very real fears that draconian cuts on this scale will destabilise the business in the short term and undermine any strategy to create a sustainable future."

But the blow has been softened by news that UKHO is to remain a MOD trading fund, thereby avoiding further organisational upheaval and retaining an invaluable national resource within the public sector.

The union will be examining the proposals with a view to offering alternatives that protect posts wherever possible. Members had drawn comfort from the announcement that the cuts are to be staged over five years.

"This will allow the unions to explore with management opportunities to find efficiencies elsewhere and minimise the impact on the south-west employment market for those unwilling to uproot their families and seeking alternative employment in the area," said Childs.

"It is hard to see how these cuts can be achieved without compulsory redundancies. Prospect will fight to ensure these are kept to the absolute minimum and on the best possible terms possible. The MOD is mistaken if it thinks it can get rid of dedicated staff on the cheap."

UKHO is a government agency, responsible for compiling and publishing information which mariners require for accurate, safe and efficient navigation at sea. Its principal customer is the Royal Navy, for whom it provides a range of hydrographic, oceanographic and geophysical products and services.

Prospect members at UKHO work across a range of specialisms including chart compilation and production, navigational textual editing and publishing, physical oceanography, geodesy, and the technical aspects of the Law of the Sea.