Explorers have returned to Lake Baikal equipped with two minisubmarines to continue a hunt for a fortune in Tsarist gold that, legend has it, was carried by Admiral Aleksandr Kolchak’s White Army as it fled the advancing Bolsheviks during Russia’s civil war.

Tales abound about the fate of Kolchak’s gold — a haul estimated at 1,600 tonnes and worth billions of pounds today. One version has it that troops retreating on foot and horsecarriage across Baikal’s icy surface froze to death as temperatures hit minus 60C (minus 76F) in the winter of 1919-20. When the spring thaw arrived, they and the sacks of Imperial gold sank to the bottom of the massive lake, which contains 20 per cent of the world’s fresh water.

Others say that the treasure was lost when railway carriages plunged into the lake from a branch of the Trans-Siberian line at Cape Polovinny. Intriguingly, one of the mini-submarines spent five hours yesterday more than 1,000 metres below the surface searching for railway carriages, after wheels dating from the civil war were found nearby.

The explorers plan to make about a hundred dives by September in the submersibles Mir-1 and Mir-2 — which were used to plant a Russian flag on the seabed under the North Pole in 2007.

The expedition is the second stage of a two-year project focused mainly on the lake’s geology and water life.

The three-man submarines descended almost 1,600 metres to the bottom of Baikal during more than 50 dives last summer, but failed to find the gold.They did, though, find ammunition boxes dating back to the civil war era.

Kolchak was a naval commander and polar explorer before leading the White Army against the Bolsheviks after the revolution, initially with strong British backing. His forces, based in Siberia, enjoyed early success but were eventually driven back by the Red Army. He was arrested in Irkutsk and executed by firing squad in January 1920. His body was thrown into the Angara River.

Organisers are reluctant to speculate on the likelihood of finding Kolchak’s gold after last year’s failure and many observers are sceptical that the bullion is in the lake.

Inna Kyrlova, the deputy director of the Fund for the Protection of Lake Baikal, one of the bodies funding the research, acknowledged that the submarines were exploring locations reputed to be linked to Kolchak’s gold, but she insisted: “Our expedition’s primary interest is the flora, fauna and geology of Baikal and monitoring current conditions in the lake.”

Finding the Tsarist treasure would be a great publicity coup for the Kremlin at a time when Kolchak’s image is being transformed from counterrevolutionary to patriotic Russian hero. He was the subject of the blockbuster film Admiral in Russia last year, which was funded by state-run television.

It portrayed him as a tragically romantic figure who gave everything to defend his motherland. Vladimir Putin, the Prime Minister, recently praised Anton Denikin, another White Army general who fought with Kolchak, as a fighter for a “great, united and indivisible Russia”.

The mission has a daunting task in trying to explore Baikal, which, after being formed 25 million years ago, is the world’s oldest lake. It is also the biggest, measuring almost 400 miles long and nearly 50 miles wide at one point.

The £4.5 million expedition has been organised by the Russian Academy of Sciences in a joint venture with a private company.

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