Every time there has been a war, we've worked a 36-hour stretch to make sure the Navy got what it wanted

Ross Burns, joint unions spokesman, Devonport dockyard

He said: "Our members feel utterly betrayed."

Armed Forces Minister Adam Ingram said the partnership with the private sector was designed to save the taxpayer more than �300m over the next five years.

He declined to say how many posts would be cut at each base, but admitted a "significant proportion" would go on the Clyde.

He said the figure of 750 was the "worst case scenario" and hoped there would be few compulsory job losses.

Ships return

Partnering contracts will be placed with existing dockyard companies - Fleet Support Ltd at Portsmouth, Devonport Management Ltd at Devonport, and Babcock Naval Services Ltd on the Clyde.

They are negotiating the fine details on five-year contracts to expand their existing work at the dockyards.

The Royal Navy's fleet has been reduced

The announcement was made on the day HMS Illustrious and HMS Cornwall returned home after service in the war against terror.

A Ministry of Defence spokesman had said beforehand that changes were needed because the size of the Royal Navy's fleet had been reduced significantly in recent years.

Mr Ingram said: "It is up to the naval dockyard companies themselves to decide what the structure of the workforce should be.

"To give figures in a precise way is not possible."

Community impact

He said work would improve: "Processes will be streamlined, work rationalised between the dockyards and naval bases, and commercial expertise and best practice introduced," he said.

Ross Burns, joint unions spokesman at Devonport, said: "To say that they do it better under privatisation is rubbish.

Devonport has centuries of naval service

"My loyalty as a civil servant has been that every time there has been a war in which the Navy has been involved, we've worked a 36-hour stretch to make sure the Navy gets what it wants.

"If I am put to a private company what am I going to concern myself with - the Navy, or the profits of that private company?"

Workers likely to be affected include cleaners, cooks, civil servants and maintenance workers.

The new arrangements will cover engineering and waterfront support, together with some logistics and estates management.

Contracts will be signed next month, with work expected to switch to the private companies later in the year.

The dockyard companies are also having their existing contracts extended so they can bid for more work on refits and repairs of surface ships.

The First Sea Lord, Admiral Sir Nigel Essenhigh, said the Royal Navy Commodores at the three bases would remain in direct control of the work.