A cargo ship that has gone missing after passing through the English Channel may have been the victim of a new kind of piracy, marine intelligence experts said today.
They said the 4,000-tonne, Maltese-flagged Arctic Sea may be heading for the west coast of Africa - scene of many pirate incidents in recent months.
But the experts and other marine authorities continue to be baffled by the fact that the ship has "disappeared" since its last recorded sighting off northern France on July 30.
The ship, with 15 crew aboard and carrying about £1 million-worth of sawn timber from Finland to Algeria, made radio contact with Dover Coastguard as it was about to enter the Strait of Dover on July 28.
The ship should have arrived in Bejaia in northern Algeria on August 4.
According to reports, Swedish authorities were told by the Finnish shipping line operating the vessel that on July 24 it was boarded by up to 10 armed men purporting to be anti-drugs police as it sailed through the Baltic Sea.
Some 12 hours later the intruders apparently left the ship on a high-speed inflatable boat and allowed the vessel to continue on its passage but with its communications equipment damaged.
Then, on August 3, Dover Coastguard was informed by Interpol that the crew had been hijacked in the Baltic Sea and was asked to be alert as it passed through the Channel.
But the Arctic Sea had already completed its voyage through the Strait of Dover. It was last recorded on the AISLive ship tracking system off the coast of Brest, northern France, just before 1.30am on July 30.
Marine intelligence expert Graeme Gibbon-Brooks told Sky News today: "If this is a criminal act, it appears to be following a new business model.
"It seems likely that the vessel will head for the west coast of Africa."
He said it was quite usual for vessels carrying timber to be seized, the timber unloaded and the ship repainted, with a number of instances taking place in south east Asia.
Nick Davis, who runs private security firm Anti-Piracy Maritime Security Solutions, told the BBC's Today programme: "Piracy is piracy - if someone's wanting to take that vessel, and they're not authorised, and they use a speedboat to go and get it, then it's no different to what the Somalis do.
"However, I don't believe they would have boarded that vessel firing weapons in the air, and threatening to kill the crew. While it is piracy, it's not like what we know in Somalia."
Mark Clark, of the UK's Maritime and Coastguard Agency, said Dover Coastguard was unsuspecting of anything untoward as a supposed crew member radioed before the ship journeyed through the Channel - one of the world's busiest waterways.
Mr Clark said: "The ship contacted Dover Coastguard on July 28 and that was the last time anyone has heard from them.
"There didn't seem anything suspicious when contact was made. It could well be that a crew member had a gun put to his head by a hijacker when contact was made, but who knows?"
He went on: "It's bizarre. There is no coastguard I know who can remember anything like this happening. Who would think that a hijacked ship could pass through one of the most policed and concentrated waters in the world?
"It seems strange to think that a ship which had been hijacked was passing along the Channel along with ships carrying day-trippers going over to Calais for the day."
Mr Clark said an innocent explanation was improbable but he added: "We are extremely curious to find out what could have happened to this vessel."