THE end of an era in Britain's Cold War history was marked yesterday by the lowering of the White Ensign on HMS Repulse, the country's last Polaris submarine.

It was the penultimate act in a decommissioning ceremony at Faslane naval base on the Clyde, attended by Prime Minister John Major and Defence Secretary Michael Portillo. It ended almost 30 years when four Polaris submarines protected Britain by supplementing Nato's strategic nuclear forces.

The Polaris vessels have been replaced by the new Vanguard class submarines, which are twice as big and carry the more powerful Trident missiles. HMS Vanguard and HMS Victorious are in service, HMS Vigilant is undergoing sea trials, and HMS Vengeance is at the construction stage.

Yesterday belonged to the 425ft, 8000-tonne HMS Repulse, built in 1967 with a design capacity of 16 Polaris missiles. Resolution, Renown, and Revenge have already been decommissioned.

They will be stripped down to their nuclear reactors and then kept at Rosyth, Fife, while the nuclear waste disposal agency, Nirex, builds a permanent, safe dump site for the radioactive material.

At yesterday's ceremony, the Prime Minister paid tribute to the men who served on the four submarines - and to their families who had endured long periods of separation while the vessels lurked under the waves for an average of three months at a time.

Mr Major said: ``I have no doubt that we are right to maintain a minimum credible strategic nuclear deterrent for the UK. We will continue to do so for as long as our security needs require us to do so.

``It would be folly for us to act differently. Even though circumstances have changed, the world still remains an uncertain and dangerous place.''

The man who commanded HMS Repulse's first patrol in 1968, Rear Admiral Tony Whetstone, described the decomissioning ceremony as a mixture of nostalgia, pride, and sadness.

Commanding a submarine which was capable of causing nuclear devastation to targets almost 3000 miles away was an unforgettable and sobering experience. ``You had to think about it, come to terms with it, and then, to a degree, forget about it.

``You couldn't live your whole life saying `what is going to happen if I press the button?' You had to come to terms with the fact that you had this enormous power and, of course, you were sustained by the fact that it was a great preserver of peace because of its awesome nature.''

The ceremony was attended by about 1000 guests, including many of those who served in the submarines and Lady Zuckerman who launched the ship. The audience was addressed by Commander David Philips, the last commanding officer of HMS Repulse, followed by prayers, hymns, and the Royal Marines Scotland playing the Last Post before the flag was lowered. Afterwards, a piper played Auld Lang Syne and the ships' company stood in silence in tribute.

Polaris has made Faslane a focus for anti-nuclear demonstrators camped outside the base for the past 14 years and the 10 protesters who currently occupy the brightly coloured collection of caravans and mobile homes yesterday pledged to remain there for as long as Trident did.

Some of them draped banners at the north gate of the naval based declaring ``Trident. Major mistake'' and ``Polaris gone. #33bn Trident remains''. Others used canoes to paddle close to a launch carrying the Prime Minister on a tour of the base.

CND, in a briefing paper on the end of the Polaris era, claimed yesterday that storing Britain's redundant nuclear submarines would cost #225m over 11 years.

It detailed technical problems with Polaris boats during their history and said that, though the Royal Navy hailed the decommissioning as the end of an era, ``the truth is that it was the end of one of the biggest headaches the Royal Navy has ever had to deal with''.

Mr Portillo said yesterday that he believed storage facilities for the reactors from Polaris submarines were ``entirely safe''.

He also rejected claims that there would be a huge cash saving in scrapping the final Trident. The fourth vessel was needed to make sure there was always at least one on patrol where no enemy could take it out of action with a pre-emptive strike, he said.

SNP defence spokeswoman Margaret Ewing demanded to know how long the decommissioned submarines would stay at Rosyth. ``The people of Fife and Scotland will react with fury to the news that the London Government view Rosyth as nothing more than a convenient rubbish tip for dead nuclear submarines.''

Councillors there have warned that the presence of the submarines could jeopardise a a multi-million pound port, industrial estate, shopping park and housing development.

The plan for the old Rosyth Naval Base was unveiled yesterday by Rosyth 2000, a constortium involving ScottishPower, Forth Ports, Bank of Scotland, and Babcock. The outline development plan covers 144 hectares of the old base and also includes leisure facilities and amenity protection areas, particularly for the ruined Rosyth Castle and St Margaret's Marsh. There is also a park-and-ride facility for the whole complex.

But some councillors warned the consortium that the submarine hulks could hold back the ultimate development of the Rosyth area.

Mr Sandy Cook, area planning officer, told the West Development Committee the plan was still only in the outline stage but the consortium could not buy the site from the Defence Ministry until planning permission had been obtained.

HMS Repulse, the 13th Royal Naval vessel to bear the name, had gone home to Faslane in May, after completing the last of its 60 patrols. Its motto - Qui Tangit Frangatur - translates as ``Who touches me is broken''.

During each patrol, the ship would have remained submerged and undetected. Only a tiny group of people ever knew its precise position.

Birds that never flew -- 17