Divers have started exploring the wreck of a British submarine off the Grand Harbour that, until 2011, had remained untouched for 70 years. It is believed that some 90 men died when the HMS Olympus sank off Malta in 1942, probably after hitting a mine.

The 86-metre long vessel was one of the subs that used to run essential supplies to Malta. Until the fateful night of May 8, it played an important role in what became known as the Magic Carpet Service, ferrying passengers, fuel, ammunition and food from Gibraltar to Malta.

On that day, it was in fact carrying survivors from ships that had been sunk. About 100 people were aboard. Only 11 survived.

In 2008, a team of technical divers from the UK and Malta believed they had found the wreck but it transpired that it was not the HMS Olympus.

The submarine was finally located in 2011 by marine archaeologist Timmy Gambin.

That year, he led a team of researchers to the Olympus using side scan sonar equipment. Explorers then returned to the site with a remotely operated vehicle to capture images and verify its identity. But they still needed to confirm what had led to its sinking.

It was only this summer that explorers from U-Boat Malta Limited, a company that specialises in marine archaeology, dived 120 metres to explore the vessel.

“HMS Olympus was one of the last remaining undiscovered warships from World War II and it provides further material evidence of the conflict that raged off the Maltese coast,” Dr Gambin said. The team gathered vital information on the damage suffered by the submarine to help them understand the circumstances that led to her loss. The team is planning more dives on the Olympus.