It is by any standards a strange state of affairs. The command deck of this Foxtrot U-475 submarine, where once Soviet officers could have unleashed nuclear warheads against Nato targets, will soon be overrun with London children more interested in the complex dials and shiny brass fittings than the intricacies of the Cold War.

Perhaps that is just as well. Although now under the scrutiny of Western eyes, many of the secrets of this Soviet submarine, which will be the first to be viewed in Britain when she opens to the public on Friday, remain submerged in its past.

She has been moored at the Thames Flood Barrier in Woolwich by Russian Submarines UK, the company that purchased her in June for an undisclosed sum and had her sailed over from the Latvian port of Riga.

According to the company, every detail of its covert missions is carefully noted in logbooks which now lie hidden deep within Russian government archives and are unlikely to be revealed.

Ben Wrede, one of the partners in Russian Submarines UK, said: 'All the Russians will tell us is that after 1976 she was used specifically for training foreign submariners, including people from Cuba, India and Libya.

'Before that all we can do is guess where she went and what she did. We've asked but they won't tell us.'

We do know, however, that she was launched in 1967 as a Cold War surveillance vessel fitted with state-of-the-art observation and monitoring equipment, a capacity to travel at 16.8 knots and enough torpedoes to sink several battleships.

During the Sixties and Seventies she trawled the Indian, Atlantic and Pacific Oceans, listening to the West.

She would often lie just a mile offshore, where the radio operators (protected against mutiny by the thick steel door of their control room) could pick up land frequencies quite clearly.

Conditions inside were gruelling, with 75 men spending up to three months underwater sharing two lavatories and one shower, and sleeping in hammocks slung across roaring engines and between hissing pipes.

Temperatures inside the thick inner hull often rose to 50C when the engines were at full speed and the tight central artery of the submarine allowed barely enough room for two burly sailors to pass.

KGB officials, present on every trip to ensure loyalty, were feared and disliked by captain and crew, who considered them 'dangerous moles.

However, despite these hardships and the strict on-board discipline, almost all the crew were volunteers, attracted by the promise of more pay and longer holidays than they could get from factory jobs back home.

The submarine, originally part of the Baltic Fleet was the largest non-nuclear type in the Russian Navy. She was decommissioned in April and went on sale after the break-up of the former Soviet naval forces.

She was sailed to London in July by Captain Vitalij Mikhailovich Burda who, before bidding a final farewell to the vessel that had been his second home for 23 years, recounted some of his experiences and apologised for treating the West as a hostile foe.

Teams of electricians and welders are now the crew of U-475, working round the clock to prepare her for Friday's official opening.

However, Mr Wrede is keen to emphasise that she is not a museum. 'It's an experience, a chance to feel what it was really like to live and work on one of these, he said.

To make the 'experience as authentic as possible, he and his business partner Mark Sturton have altered only a minimum of the submarine's interior and most of it is still exactly as it would have been when she was in active service.

From Friday Foxtrot U-475 will be open to visitors every day, 10am to 6pm. She is moored at the Thames Barrier on the south bank of the river in Woolwich. Admission is pounds 3.95 for adults, pounds 2 for children under 14 and pounds 9.90 for a family ticket.

Ten facts about Foxtrot U-475

She could travel 30,000 miles before having to refuel.

She could dive to a depth of 1,100 feet and travel submerged for a maximum of 400 miles.

She carried 22 torpedoes, 18 forward and four astern.

Russian Submarines UK had to wait a month for the right water levels to dock her at Woolwich without running aground, because her height is the same as that of a high tide.

The youngest crew member was 19 and the oldest 50.

Men conscripted to serve on her had the option to leave after a year.

In the late Eighties, general seamen earned slightly more than pounds 2 a month

one thirtieth of an officer's pay.

The food was considered to be excellent and the crew enjoyed four meals a day: full cooked breakfast (sausage, cheese, egg, cereals), four-course lunch (fruit juice, borsch, meat/fish/poultry and stewed fruit), dinner (hors d'oeuvre or salad, meat/fish/poultry) and evening tea (tea or milk, biscuits, jam and curd).

Cigarettes were forbidden while submerged because of air pollution, but five men at a time were allowed into the conning tower when they surfaced.

The only women allowed to board were cleaners when she was in port.

(Photographs omitted)