The drama tells the true story of the amazing heroism shown by ordinary people in the face of extraordinary adversity during the Second World War.
Brian Cox plays Captain Sharp, whose armed British vessel, the RMS Laconia, was torpedoed and sunk by German U-boat 156 on 12 September 1942.
Also on board was 3rd officer Thomas Mortimer (Buchan), who heroically risked his life to help the passengers reach the lifeboats.
Six hundred miles from the coast of Africa, the mixture of civilians, Allied soldiers and Italian Prisoners of War faced certain death until U-Boat Commander Werner Hartenstein (Duken) made a decision that went against the orders of Nazi High Command.
The U-boat surfaced and Hartenstein instructed his men to save as many of the shipwrecked survivors as they could.
Over the next few days the U-156 saved 400 people, with 200 people crammed on board the surface-level submarine and another 200 in lifeboats.
Hartenstein gave orders for messages to be sent out to the Allies to organise a rescue of the survivors but, in an unbelievable twist, they were spotted by an American B-24 bomber who moved in to attack.
Laconia takes a look at the human side of the remarkable events that took place: the friendships that developed, the small acts of heroism, and the triumph of the human spirit in the most incredible of situations.Genre: