A HUGE search-and-rescue operation launched after a tug capsized and sank on the River Thames in London has tonight been called off.

The search for the crew member who has been missing since the tug capsized and sank on the River Thames this morning was called off as marine accident experts began an investigation into the accident.

Two other crew members were safely rescued after the tug, called Chieftain and which was towing a barge with a crane on it, went down off Greenwich Pier in south London, just before 11am.

A major search-and-rescue operation was launched for the missing crewman, with efforts being co- ordinated by the Woolwich-based London coastguard.

But about four hours after the sinking, the Maritime and Coastguard Agency said the search – involving police, the Port of London Authority, the fire brigade and lifeboat crews – had been called off.

The section of the river around Greenwich Pier had been closed while the search had gone on.

The MCA said: “The Port of London Authority (PLA) is beginning the first stages of an operation to raise the sunken tug. Depending on the circumstances, this will be carried out by PLA or by a salvage contractor.

“The Marine Accident Investigation Branch have begun an investigation into the causes of the accident. The incident is also being investigated by the MCA survey and inspection branch.”

At the scene of the accident, a second tug boat, which river workers said was also attached to the barge, was still afloat and activity could be seen on deck.

One onlooker said they went to the riverside shortly after the incident at 11am but by then the boat was underwater.

One passer-by who witnessed the sinking said: “The front tug seemed to hit a buoy and capsized. It was submerged within a matter of minutes. I saw two men being pulled out of the water on the other side of the river.”