Scuba divers searching the first British warship to sink in the First World War have made a “remarkable” discovery.

A lifeboat, which is still intact despite the vessel sinking in 1914, was identified by divers from the Ipswich-based branch of the British Sub-Aqua Club – iDive – along with decking during a five-day exploration of the HMS Amphion last week.

Based some 40 miles off the coast of Harwich, the shipwreck is a lasting reminder of the tragic events of August 6, 1914, when the vessel struck a mine laid by German ship the Königin Luise – killing 132 Britons on board.

Just two days earlier the Amphion, built in Pembroke Dock in west Wales, had been sent to patrol the North Sea between Harwich and the German sea area of Heligoland Bight following the outbreak of war.

The club’s diving officer Dave Lock, who says exploring the Amphion’s wreck has been a lifelong ambition.

He said: “The Amphion has actually split into two sections, the stern and her bow. We only dived on the bow section which sits upright with the hull still intact.

“There is a great deal of wooden decking which is still visible and shows that they must have used good-quality timber for it to have survived 102 years under the North Sea.

“Poignantly, considering the loss of life, we also saw a lifeboat which is still attached to the wreck. I only glimpsed it as it was some distance from where I was diving but it drives the message home somehow that this is a war grave.”

Now the divers, from Felixstowe, Ipswich, Wattisham and Otley, are appealing for relatives of those who perished on the ship to come forward and tell their stories.

Issuing a call for them to get in touch, Mr Lock said: “I would love to hear from anyone who lost a relative on either the Amphion or Königin Luise. It’s always a bonus to be able to hear and be able to piece together some of the stories surrounding any shipwreck.”

Mr Lock, a retired radio engineer who took part in the dive with Paul Mann, from Felixstowe, Matt Yates, from Wattisham, Paul Shannon from Ipswich, and Raj Mistry from Otley, added: “We did have a few moments of quiet reflection as we dived on the wreck.

“And of course, as responsible BSAC divers we would never touch or remove anything from any wreck.”

The wreck is a protected site, so any search of it must be done on a “look but don’t touch” basis.