The 2,000-tonne vessel, which had been carrying grain from Lübeck in Germany, sank at about 8am yesterday.
Mario Siano, the watch manager at Yarmouth Coastguard, said that an investigation was under way to find the cause of the incident. "The captain of the ship is in police custody and the rest of the Polish crew are being housed in a local hotel," he said, adding: "It's a routine thing for captains to be breathalysed in situations like this. There will be all sorts of checks done."
Mr Siano said the chances of such a crash are "minimal" as there is a 500-metre exclusion zone around platforms. The vessel sank after its hull burst, caused by the wheat on board "swelling", but pollution caused by the accident was "minimal".
He added that the pipeline to the gas platform, which was not badly damaged, had been shut down.