Dr John Large, a nuclear expert who has advised the Royal Navy and helped Russia raise the Kursk submarine, called the proposal "sheer lunacy".

BBC: Plan for nuclear submarine return

Negotiations on joint submarine search and rescue operations - an initiative that sprang from the Kursk submarine disaster in August 2000 - are also well advanced.

BBC: Analysis: Nato and Russia draw closer

Dutch shipping and salvage firm Smit International - which helped raise Russia's Kursk submarine - has formally submitted a proposal to the Spanish Government and the European Union officials to salvage oil from the wreck.

BBC: French sub to try patching Prestige

Yet there are some startling gaps, such as the sinking of the Kursk submarine and the terrorist atrocity in Beslan itself a turning point in Mr Putin's approach to the West, which he implicitly blamed for Chechen terrorism.

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There has been mixed reaction in the Russian media to the plight of the submarine "Kursk".

BBC: Russian media asks 'What happened?'

Such an explanation would perhaps be easier to believe, were it not for the fact that the Kursk is the largest submarine in the world, and, unlike any Western submarine, has a twin-hull, the inner skin of which alone is 40cm thick.

BBC: Aftermath of the Kursk tragedy

The navy has tried to convince anyone who would listen that the Kursk was struck by a foreign submarine, which then sailed away.

BBC: Aftermath of the Kursk tragedy

The idea that a smaller submarine could have struck the Kursk and sailed away, whilst the Russian giant sank to the bottom is difficult to imagine.

BBC: Aftermath of the Kursk tragedy

Two explosions on board the submarine had been monitored, making it clear that the bow of the Kursk had been ripped open, and the vessel had sunk to the bottom like a stone.

BBC: Analysis: Kursk cover-up

The Russian navy has received a new nuclear missile submarine which has an escape capsule, to avoid any repetition of the 2000 Kursk disaster.

BBC: New Russian nuclear sub 'safer than Kursk'