In the 1930s famine stalked the Soviet Union. The key question was how to feed the people. Thousands of words have been written about Soviet agriculture and farming but there was much less known attempt to increase food production that strangely is still having a profound effect on the natural world today.

This far less well publicised project was to relocate hoards of giant red king crabs (Paralithodes camtschaticus) from the Kamchatka Peninsula in the north Pacific to the Arctic Barents Sea off the coast of European Russia, giving the local people a rich source of easily caught, delicious and nourishing food.

Josef Stalin ordered thousands of baby crabs be moved 3,000 miles by road from the Soviet Far East to the western end of the Soviet Union.

The state of the Arctic roads and less than reliable motorised transport in harsh Arctic conditions meant very few of the tiny young crabs arrived safely — most died on the journey. The plan failed.

There was a second attempt to move the crabs in the 1960s and this time much quicker and more reliable air transport meant the job could be completed. This time large, mature and healthy female crabs were moved and they started to flourish in their new more westerly home.

As they became established they not only provided essential protein for Soviet people but also a lucrative export product.

Tinned Soviet Chatka crab was available in British shops and provided a valuable source of hard currency to the Soviet Union. It was delicious and relatively inexpensive. In the 1960s when English crab wasn’t available or out of season I filled my sandwiches with Russian crab.

This crab relocation may have seemed a good idea on the face of it, but as so often when humans seek to interfere with nature the consequences are potentially dire. Time and time again we have discovered that moving species can go badly wrong and the Soviet experiment with the giant red king crabs was no exception.

Now, half a century later, we have huge populations of very large invasive animals from foreign waters completely taking over the local ecosystem and devouring everything in their path and leaving the bed of the ocean a barren waste.

The real size and scale of the problem started to come to light a decade ago when Arctic fisherfolk were reporting the sea beds and local wildlife being greatly affected by the presence of the crabs and fearing the local cod numbers being affected.

Today millions of these massive crabs, once only native to Alaskan seas and the north Pacific, are advancing relentlessly along and down the Norwegian coasts, devouring almost everything in their path.

Reactions to this spread of the crabs are varied. Some fishing communities in northern Norway say the crab, among the largest in the world, has already had a devastating impact.

Others welcome the giant red king crab, saying its delicious taste and size — the crabs can grow to 22 pounds (10kg) and measure five feet (1.5m) across — make it an extremely lucrative catch.

Here in Britain seafood gourmets are paying as much as £40 a kilo for the delicious crab’s meaty legs. King crab is replacing lobster as a top dish in posh seafood restaurants and the once cheap and cheerful Russian tinned crabmeat is reaching the kind of prices people once paid for caviar.

Conservationists, however, are worried. The WWF Norway says the crab’s population has increased six-fold in 20 years. The environmental group puts the current population at least 12 million in the Barents Sea alone.

The group says that any economic benefits derived from this population explosion may be vastly outweighed by the long-term cost to the marine environment. For instance, WWF Norway says it is concerned about the impact of the crab — which has no natural enemies in Arctic waters — on the capelin, a fish considered central to the Barents Sea food chain.

The crab is now reported to have reached the Lofoten Islands, about a third of the way down the Norwegian coast, having migrated some 400 miles since the early 1990s.

Its spread is much faster than anyone anticipated. In its native north Pacific, where seabed competition is tougher, red king crabs have already ventured as far south as northern Japan, which is on the same latitude as southern European countries.

Scientific predictions about just how far south it will reach in Europe vary widely. Some say just south of the Arctic Circle, others predict it will reach the British east coast and still others believe as far as Spain and Portugal.

WWF Norway says the Norwegian government’s management policy towards the species has been to maximise population size to increase potential catches, while ignoring the possible consequences for the marine environment. Considering the importance of the Barents Sea as one of the world’s most productive marine ecosystems, this policy is certainly short-sighted and might be gambling with the future.

In 2003 Norway and Russia agreed to double the total annual fishing quota to 800,000 crabs. Unrestricted fishing for the species is also happening in certain areas. Strangely the US Alaska fishery for the same crab has declined and catching the severely reduced US stocks is now tightly regulated.

Will we be able to stop the red king crab’s relentless march southwards from Russia and Norway? Do we even want too? This particular crustacean has proved such a successful species when it comes to occupying new areas of ocean and demand for the delicious crabmeat will always be hard to regulate.

So often in the past human intervention, mainly overfishing, has upset the delicate balance of the oceans. Let’s not risk it again in the desire just for a nice crab sandwich.