FOR 2000 years the ancient and decomposing hulk lay buried in deep, muddy waters, off the Italian coast.

Everybody knew it was down there because for more than 80 years local fishermen had been collecting bits of Roman artefacts and pots in their nets.

Finds of this nature are not unusual in Italian waters, which are littered with treasures going back thousands of years.

But these artefacts told a different story, and it was good enough to attract the interest of the archaeological community and a police commander who heads an expert diving squad in the city of Genoa.