The investigation into why a cargo ship capsized and sank off the north coast of Scotland has begun.

The Marine Accident Investigation Branch (MAIB) was called in after the search for the eight missing crew members of the Cypriot-registered Cemfjord was suspended yesterday.

A major search effort was first mounted on Saturday after the upturned hull of the ship was spotted in the waters of the Pentland Firth and yesterday lifeboats, helicopters, and coastguard rescue teams continued to search until darkness fell.

There has been no sign of the eight crew members, made up of seven Poles and one Filipino.

The 83-metre bulk cement carrier, which had been bound for Runcorn, Cheshire, on the west coast of the UK, sank below the water yesterday afternoon.

The coastguard will continue to broadcast messages to all shipping requesting that they are informed about any information or sightings that could be related to the vessel.

The last confirmed sighting of the ship was at about 1pm on Friday.

The crew on the NorthLink ferry Hrossey alerted the coastguard after spotting its upturned hull around 10 miles east of the Pentland Skerries, about 15 miles from Wick at around 2.30pm on Saturday.

German shipping company Brise of Hamburg, which manages the ship, confirmed that there were eight people on board, adding that there had been no distress call.

The families of the missing crew have been notified.