Pressurised ascent training at the Submarine Escape Training Tank – known as SETT – at Fort Blockhouse has been stopped until the navy board meets next month.

It was due to re-start on Monday after the summer break but the navy says it has not because of the risks of the training outweigh the benefits.

The News reported back in July that submariners feared the distinctive 100ft tower would be closed because most submarine training is now done in Scotland at Rosyth.

The emphasis has also moved to sending rescue submersibles down to stricken subs, instead of submariners escaping themselves.

At the time the navy refused to confirm the details of the review, and the decision to suspend training has only heightened fears the building could be scrapped.

Defence select committee member and Portsmouth South MP Mike Hancock said: 'The Sett tower is an integral part of the submarine heritage of Gosport and I would hate to see it demolished.

'Every submariner has gone through that training and it's part of what makes Gosport famous.

'The decision to stop ascent training seems to suggest that the navy think they can do the training elsewhere more effectively.'

A serving submariner, who did not want to be named, said: 'It is a badge of honour to have done the escape training, and I don't know why we have stopped it.'

But a navy spokesman said the Sett tower will still host other submarine training. He said: 'A review indicated that training could be given in a more appropriate manner, so after consultation we have decided to suspend pressurised training pending a Royal Navy board decision in October.'