Just days before the Battle of Britain began in July 1940, more than 800 civilians were killed off the coast of Ireland when a German U-Boat sank a converted five-star cruise ship.

The people on board were German, Austrian and Italian internees – deemed enemy aliens by the UK government – who were being deported to Canada.

Why the Nazis sank a civilian ship has never been fully explained.

But the sinking of the Arandora Star remains one of the lesser known war crimes of the second world war.

My research has examined the oral histories of some of the Italian families, based in the UK, who remember the second world war. My latest project has looked into the long-term effects of Arandora Star sinking as it was experienced and transmitted across generations.

The Arandora Star was a first class cruise liner built in 1927 by the Cammell Laird Company Ltd, in Birkenhead, near Liverpool. It was one of the best-known ships in the world at the time.

When the war broke out, the Arandora, like many commercial ships, was placed at the disposal of the British government. Under the command of Captain E.W. Moulton, the Arandora was ordered to carry German, Austrian and Italian internees from Liverpool to Canada.

More than 1,600 men were forced onto the ship which was actually designed to carry 500. Internees were crammed below decks and the exits were guarded by barbed wire.

On July 2 1940 – the morning after it embarked on its voyage – the Arandora was torpedoed by a German U-boat, 100 miles northwest of Ireland.

Around 805 men, over 50 percent of the total number drowned, were........

© The Conversation