Launched on the Clyde, Scotland, in 1920 by William Beardmore and Company of Glasgow, Scotland as the Tyrrhenia for the Anchor Line, a subsidiary of Cunard, the 16,243 ton, 578 foot (176 m) long liner could carry 2,200 passengers in three classes. She made her maiden voyage on 19 June 1922.
She was refitted for just two classes and renamed Lancastria in 1924, after American passengers complained that they could not properly pronounce Tyrrhenia. She sailed scheduled routes from Liverpool to New York until 1932, and was then used as a cruise ship in the Mediterranean and Northern Europe. In 1934, the Catholic Boy Scouts of Ireland chartered the Lancastria for a pilgrimage to Rome.
With the outbreak of the Second World War, she carried cargo before being requisitioned in April 1940 as a troopship, becoming the HMT Lancastria. She was first used to assist in the evacuation of troops from Norway.
She was sunk off the French port of St. Nazaire while taking part in Operation Ariel, the evacuation of British nationals and troops from France, two weeks after the Dunkirk evacuation.
It is the worst single loss of life in British maritime history and the bloodiest single engagement for UK forces (in terms of lives lost) in the whole conflict, claiming more lives than the combined losses on Titanic and Lusitania.