- By ITV News Content Producer Mark Dorman
On Tuesday, in the Canadian port of Halifax, Nova Scotia, around 80 people will gather to remember the lives lost in extraordinary circumstances off the coast of Ireland 80 years ago.
Only hours earlier that day, at 11am on September 3 1939, Prime Minister Neville Chamberlain had addressed a silent British nation over their radios to inform them the UK was once again at war with Germany.
Around the same time, the 1,100 passengers and 300 or so crew on board the SS Athenia, a British liner headed for Montreal, were undergoing a lifeboat evacuation drill somewhere off the coast of Ireland.
Within eight hours of Chamberlain's statement that Hitler could only be "stopped by force", those on board the Athenia would become the first casualties of the Second World War - targeted in error by U-boat torpedoes.
What followed is a story of survival, denial and Nazi cover-ups.
'I'd just been put to bed when that damn torpedo hit'
Seven-year-old Philip Gunyon was travelling on the Athenia passenger liner, with his mother, Andreana, together with Barbara, his younger sister, and brother, Andrew.
They were among the civilians, many Americans and Canadians, as well as hundreds of Britons, heading for Nova Scotia as people took flight from the impending war in Europe.
"We - my sister, my brother and I - had just been put to bed when that damn torpedo hit," the 87-year-old told ITV News.
"There was a great big boom and she slowing started listing.
"I have no vivid memory now of fear, only a wondering of who would come and tell us what next to do. The stewardess arrived first, followed very soon by mother.
"My mother was eating dinner - she had just started her soup, she said.
"She made her way back to us through the dark as all the lights had gone out."
The family had bunks in cabin class, so not in the bowels of the ship, and was able to get to the promenade deck relatively quickly.
The lifeboats had already been deployed but were hanging out over the sea.
"Because of the way the Athenia was listing, they had to swing the lifeboats in and out to put the children on board," he recalls.
"Looking down I saw the dark and angry waves below. As the lifeboat swung into the rail, I was pitched headlong into it and grabbed by helping arms. How mother made it with the two other children, I don’t know, but she did."
Mr Gunyon said the night in the lifeboat was uncomfortable but there was no real sense of panic among the passengers or crew.
Mr Gunynon has described his experience on www.athenia.info, where he wrote: "We were fortunate enough to have an American sea captain in our boat and he took charge and did it well.
"People took turns with the rowing through the night, including Athenia’s nurse, a steward and an elderly American gentleman who had been at mother’s table."
On September 4, a small flotilla of rescue ships had arrived at the scene and he was picked up by HMS Electra.
A bedtime story that had to be finished
Heather Donald - now Watts - was just short of her third birthday when she and her mother, Mary, boarded the SS Athenia.
While too young to recall in detail what happened that night, the 82-year-old has relived it over the years through her mother's memories, writing it down and recording it.
"It was that at about 20 minutes to eight on the evening of Sunday, September the 3rd, we were sitting in our cabin dressed in our night clothes and reading a bedtime story, when there was what my mother described as 'an almighty jolt' and all the lights went out," she wrote on www.athenia.info.
"The ship listed over and the engines stopped. There was a dead silence."
They quickly made their way to the lifeboat station but the boat was overloaded.
Crewmen could not hold it and it crashed 8ft onto the surface of the sea, damaging the rudder.
Heather told ITV News: "Our departure from the ship was not all 'calm and orderly' because we were in lifeboat 11a, which crashed the last short distance into the water and was damaged by the impact, which threw all the occupants into the stern and covered them with sea water and black engine oil.
"My mother and others had to bail for the 11 hours we were in the lifeboat, using whatever they had - in her case, her slipper.
"She got the fur coat round us and then, when things had settled down a little, at my request she finished the bedtime story.
"My only regret is that she never could remember the name of the bedtime story that she finished in the lifeboat!"
The German U-boat was spotted by those on the lifeboats as it surfaced following the attack but vanished soon after.
A few hours later, a Norwegian freighter, the Knute Nelson, found the scene and began taking on survivors.
Why was the Athenia mistakenly targeted?
Oberleutnant Fritz-Julius Lemp, commander of U-30, was on his 13th day at sea. He received information at 1400 hours that Germany was at war with Britain.
He had been told before leaving port to be aware of "armed merchant cruisers" and so, when on the surface in his operating area about 250 miles off the west coast of Ireland at about 1900hrs, he saw a vessel in the twilight.
He ordered his U-boat to dive and, believing the ship he'd viewed on deck and through the periscope to be a legitimate target, ordered torpedoes to be loosed.
Four were sent on their way; two missed but two hit home, striking the unarmed SS Athenia.
In total, 98 passengers and 19 crew died as a result of the torpedo hit and the capsizing of lifeboats as the passenger liner was lost to the sea.
Search for the wreck of the SS Athenia
Decades later, David Mearns made a breakthrough.
The marine scientist and wreck-hunter had been commissioned to see if he could locate the final resting place of the SS Athenia.
Using the latest sea-floor sonar mapping technology provided by the Geological Survey of Ireland, he pinpointed a wreck off Rockall Bank, some 260 miles from the coast of north-west Ireland.
After studying the damage to the hull, measuring the size of the wreck, in October 2017, he concluded he had found the Athenia.
To Mr Mearns, this was cause for major excitement as, he told ITV News, the sinking was a "very significant incident".
He said: "It was basically the first shot fired in the Second World War; a monumental blunder by the U-boat captain which led to a huge conspiracy and cover-up."
A cock-up and then a cover-up
The sinking of the SS Athenia came not only hours after war was declared but also on the same day Winston Churchill was appointed First Lord of the Admiralty.
Churchill was desperate for the US to get involved in the war.
But Washington - through Joseph Kennedy, the US ambassador to the UK and father of future president JFK - wanted nothing to do with joining a European war.
Soon after the Athenia attack, the Nazi propaganda machine swung into action.
The Germans spread the story that it was the British - and Churchill, specifically - who had ordered the attack on the ship carrying North Americans in an effort to lure the United States into the fighting.
Despite numerous eyewitness accounts, the Germans refused to admit the U-boat commanded by Lemp had fired upon the unarmed vessel.
It wasn't until well after the war, during the Nuremberg trials, that the truth finally emerged.
How Commander Lemp also triggered the end of war
According to historical documents, U-30 commander Lemp took the first steps to conceal the facts by omitting to make an entry in the submarine's log and swearing his crew to secrecy.
Later, more attempts were made to cover up what had happened.
Wreck-hunter Mr Mearns told ITV News it was the "first and only" time that an official U-boat log was doctored, with pages ripped out and others put in.
Lemp continued his U-boat service before his death in conflict sparked another remarkable twist in his story.
In May 1941, while on another boat, the U-110, he came under attack by three British ships in the north Atlantic, south of Iceland.
Lemp ordered his crew to abandon ship, set about scuttling the vessel and then left himself. He was not one of the survivors of U-110 picked up by the British warships and is recorded to have died in 1941.
And yet, while he is remembered for mistakenly firing the most significant first shot in the war, he also - inadvertently - triggered the start of bringing the conflict to an end.
For though his U-110 boat sank in the Atlantic there was still enough time for British seamen to climb aboard, grab vital German code books and, crucially, a small wooden box housing a typewriter.
It was this prized Enigma machine, given to codebreakers at Bletchley Park, which would prove a major breakthrough for the Allies, bolstered by America's belated entry, to second-guess the Nazis and, in 1945, win the war.