Irish soldiers told Germans of WWI tank attack plans, claims book
Organised amid the utmost secrecy, the assault on the French village of Flesquières should have been a key element in the first mass tank attack in history.
But the plan went awry when the attack was ambushed by the Germans, who managed to delay the British advance. For years, historians struggled to explain why the enemy had obtained enough detail of the operation to rush reinforcements to Flesquières before the assault.
Only now, 100 years on, can it be disclosed that the Germans were given notice of the attack by a group of captured soldiers. The betrayal appears to have been the result of growing hostility to British rule in Ireland.
The operation to breach the formidable German positions near the French town of Cambrai, known as the Hindenburg Line, relied on complete secrecy and involved using more than 350 tanks in a daring tactical experiment. However, just two days earlier - on November 18, 1917 - six soldiers from the 36th Ulster Division had been captured during a trench raid.
The Ulster Division had grown out of the fiercely loyalist Ulster Volunteers, but during three years of fighting its strength had been depleted, forcing it to recruit from Catholic areas of Ireland. As a result, German interrogators appeared to have had little difficulty extracting intelligence.
The interrogation report, published in 'Deborah and the War of the Tanks', by John Taylor, notes: "A great animosity prevails towards England … They [prisoners] say if an uprising takes place in Ireland, they would take up arms against England without more ado."
Adding to the sense of resentment was the fact that the Ulster Division had been stationed in No Man's Land, to divert attention away from the elite 51st Highland Division and tanks massed just yards from the German lines - leaving them vulnerable to eventual capture.
The impact of the men's betrayal was serious enough to hamper the entire assault.
Precisely which of the prisoners betrayed the operation is unclear, as the German report does not identify informants.
But while two of the prisoners were Ulster Protestants and two others were English, two were Irish Catholics, who may have harboured resentment about the suppression of the Easter Rising the previous year.
The book discloses that one was Pte Neil McCauley (28), from Derry, whose cousin had died at Gallipoli. The other was Pte Laurence O'Brien (26), from Co Wicklow, who had been injured in the raid and had put up a fight to avoid being captured.