A hundred years ago a ship sunk in the Irish Sea, causing more than 500 deaths – here's what its legacy can teach us about Brexit

An independent Ireland which deliberately erased its First World War history after its brutal war for freedom has only in recent decades felt able to acknowledge its people’s sacrifice in British uniform

You’d think that the 100th anniversary of the sinking of a Royal Mail ship – torpedoed in the Irish Sea in 1918 with the loss of 569 lives – would cause a few ripples in Brexit Britain. Most of the 771 passengers aboard were British soldiers heading back to the Western Front to fight for France. One of the engineers came from Birkenhead, a ship’s trimmer from Holyhead. There were Americans, Canadians and New Zealanders among the dead. So revolted was US president Woodrow Wilson by the sinking – for the RMS Leinster was also carrying more than a hundred civilians – that he delayed replying to a German request for an armistice.

The Leinster, the regular daily ferry to Holyhead, was sunk 100 years and a day ago, the greatest ever disaster in the Irish Sea, and scarcely a month before the end of the First World War. But yesterday in Britain, only a mention in the Welsh press, a local BBC report and a minute’s silence at the Holyhead cenotaph commemorated the event. Obversely, the nation which suffered the greatest loss of life aboard the Leinster hardly bothered to remember its sinking until recent years. And the reason is simple. For most of the British soldiers aboard were Irishmen and the ship was a Dublin vessel and the 22 postal sorters killed were Irish and it sank less than an hour after it left the Irish port of Kingstown which is now called Dun Laoghaire.

And this has produced an extraordinary irony of both history and politics. An independent Ireland which deliberately erased its First World War history after its brutal war for freedom from Britain – then a civil war within its 26 county borders – has only in recent decades felt able to acknowledge its people’s sacrifice in British uniform on the Somme, Flanders and at Gallipoli. And aboard the Leinster. And so it was that yesterday morning, led by the Irish naval service patrol ship Orla, a small flotilla of boats set sail from Dun Laoghaire – once a great royal navy port – so that descendants of the dead could scatter wreaths only a hundred feet above the wreckage of the Leinster. The Irish Times devoted a whole page to the disaster. Irish national television carried a prime time documentary on the Leinster.

The ship is still there, of course, virtually cut in half by the two torpedoes fired into it at 9.50 in the morning of October 10, 1918, by the German submarine U-123. Not long ago, an Irish diver found human remains still on the seabed. Another, in 1984, found a batch of 12lb British army artillery shells in racks inside the wreckage. For the twin-funneled Leinster, one of four mail ships running the daily service to Holyhead, carried its own armament, was painted in almost impressionist camouflage designs and would have appeared a military target to Oberleutnant Robert Ramm when he saw the ship on a morning as bright and blustery as it was yesterday a few miles east of the Kish lightship – now a lighthouse – outside Dublin Bay. The British later refused an official enquiry into the destruction of the Leinster.

The story of the sinking, virtually forgotten in the UK but remembered in Wales – whose people have joined with Dun Laoghaire for years in commemorating the sinking – was the stuff of every naval tragedy. Most of the servicemen were returning from leave in Ireland although there were businessmen travelling to Britain, nurses, and a mother – Fanny Saunders – sailing to visit her gravely ill daughter. The ship left the Carlisle Pier in Dun Laoghaire at 9am sharp. Just after breakfast had been served, passengers on deck saw a torpedo track, which missed the ship. But a second torpedo from the U-123 exploded in the mailroom amidships, where the Dublin postal workers were sorting the cross-channel letters and parcels, and a third torpedo finished off the Leinster.

British Admiralty rules forbade captains from stopping to help a stricken vessel – for fear their own ship might be torpedoed – and so the dying survivors saw other ships passing them as they clung to pieces of wreckage. One of the first rescue ships to reach the scene was the British gunboat Helga, which had shelled Irish rebels in Dublin during the 1916 Easter Rising two years earlier.

Relatives found themselves searching through “piles of bodies” lying on the pier at Dun Laoghaire. One of them identified Fanny Saunders when she saw her red shoes protruding from a blanket-covered body. Michael Collins, the IRA chief, used to hide from the British in the Dublin home of the Blake family. Jack Blake died of his wounds from the Easter Rising. His father Joseph was one of the postal sorters who perished on the Leinster two years later. Edward Lee of Blackrock, near Dublin, had lost a son, Joe, at Gallipoli and now lost another, Ernest, on the Leinster. His letter to his third son Tennyson survives. “I fear our very dear and loved son Ernest is no more in this world,” he wrote. “… May the good Lord pity our boy … Your loving and affectionate Father.”

For weeks, bodies washed up in Ireland, Scotland and Wales; one of them a young, unidentified woman came ashore near Holyhead. So did rumours: that soldiers threatened the passengers in the panic to abandon ship, that firearms were used – Sinn Fein would use this in its forthcoming election campaign. A few days later, the German U-boat U-123 was lost with all hands when it struck a mine in the North Sea.

The local council at Dun Laoghaire has just produced a fine volume on the sinking of the Leinster in which the lord mayor of Dublin, Mícheál Mac Donncha, refers to the 1914-18 war as “futile” and adds – truthfully – that “our country was brought into it without … a democratic, independent government which was denied to us by the British government.” The mayor of Holyhead, Ann Kennedy, regards the Leinster tragedy – again, correctly – as “part of the history of Holyhead and Ireland” and speaks of “the friendships that have developed between Wales and Ireland”. She does not mention Britain. The British ambassador in Dublin, Robin Barnett, concludes rather prissily that the commemorations allow us “to remember our forbears in a respectful and inclusive (sic) manner”.

But the German ambassador to Ireland, Matthias Hopfner, gets it spot on. Peace, he says, is inextricably linked to the European Union. “Europe is not only an answer to the past. It is an answer to the future.” In other words, this is not about “inclusivity” – how I am beginning to hate that smug word – but about history. Wales, alas, voted for Brexit – although there are signs it would not do so again if given a second referendum.

When Ireland “did a Brexit” by leaving the British empire after 1921 – and the Commonwealth in 1949 – it buried some of its recent history. Through pride or prejudice? But its EU membership surely encouraged Ireland to see itself as a free and confident European country which could re-examine that history. Hence yesterday’s commemorations above the 1918 wreck of the Leinster. In those days, of course, British soldiers on leave from the Western Front in France could be given a free ticket to London or Dublin. No hard borders then.