Police are appealing for the owner of a rare medallion featuring a ship sunk during the First World War to come forward.

The medallion, marking a historic event which hastened America's entry into the war, was found by police in a car in the Thornton Road area of Bradford on Wednesday, March 12.

The brass-coloured piece is in recognition of the loss of the British liner Lusitania which was sunk by a German submarine on May 7, 1915 and then used by America to explain its reason for going to war. The ship was sailing from New York to Liverpool when she was struck off the coast of Ireland. Although it was an ocean liner, the ship also had a cargo of ammunition. Historians say 1,198 drowned with more than 100 Americans among them.

Germany justified the attack on grounds that the ship was carrying ammunition made in America.

The sinking and loss of innocent lives was used by Secretary of the Interior Franklin K. Lane to explain America's involvement in the war to US citizens, in a speech he said: "We still hear the piteous cries of children coming out, out of the sea where the Lusitania went down, and Germany has never asked forgiveness of the world.... harmless, terrorized people .... sent to the bottom, hundred of miles from shore... murdered against all law, without warning."

The historic sinking was marked by German medallist Karl Goetz and his piece was later copied in Britain and used as propaganda against Germany.

The original German medallions, which show the date of the sinking incorrectly as May 5, are very rare.

A West Yorkshire Police spokesman said the medallion had a diameter of about 2ins and showed the ship on one side.

Anyone who recognises it should contact PC Dean Patterson on (01274) 376259.