THIS month 90 years ago, the Irish civil war had entered a decisive stage. The pro-Treaty provisional government had taken the momentous step at the end of September of introducing the Public Safety Act, authorising trial by military courts and the penalty of execution for a wide variety of offences.
By November, such executions of anti-Treaty republicans were a reality and, in all, 77 were executed during the civil war, which ended in April 1923.
In the aftermath of the killing of Michael Collins in August 1922 and the continued refusal of republicans to accept the legitimacy of the government, hearts had turned to stone and the public and private pronouncements of the provisional government made it clear that it believed its new ruthlessness was necessary for the state to survive.
Late 1922 was thus a time of hard choices, viciousness and tragedy, but it was events earlier that year that had ensured the civil war could not be prevented.
After anti-Treaty republicans, led by Rory O'Connor, had occupied the Four Courts in Dublin in April, Michael Collins, as head of the provisional government, and his colleagues were under considerable pressure to react to this defiance. The decision to attack the Four Courts on June 28 after the occupants had ignored an ultimatum to leave was followed by the provisional government's issuing of a call to arms.
By the end of the war, there were more than 50,000 troops in the National Army. It was a war the republicans had neither the resources nor the popular support to win.
In 1988, historian Michael Hopkinson published his acclaimed history of the civil war, under the striking title 'Green against Green', a title that spoke volumes of the tragedy for those who had fought alongside each other in the war of independence but were now in arms against each other in a conflict that divided communities and even individual families.
But there may be another twist in the civil war story that suggests it was not just green against green, but perhaps green and a bit of royal blue against green at the outset of the war.
A memoir discovered by Open University academic William Sheehan in the Imperial War Museum and written by Lance Bombardier Percy Creek of the Royal Field Artillery, suggests that his artillery unit travelled secretly to Dublin to help bombard the Four Courts because the National Army did not have powerful enough equipment to do the job effectively.
Creek's memoir appears to have been written 50 years after the event and should not be accepted as Gospel. After all, he mistakenly believed that it was Black and Tans who were in the Four Courts, and his account could well be faulty.
But if his assertions are true -- and there were certainly rumours in 1922 that British soldiers were involved -- they complicate the history of this crucial period and contradict the formal denial by the National Army at the time when British soldiers played a part.
Behind the scenes, Britain had exerted serious pressure on the provisional government after the Four Courts' occupation.
Winston Churchill, Secretary of State for the Colonies, had sent a letter to Collins: "I write to you as man to man ... it is obvious that in the long run the government, however patient, must assert itself or perish and be replaced by some other form of control."
It was this tone and this threat from London that would have been a major consideration for the provisional government in deciding to move against the Four Courts garrison. Collins was desperate to avert civil war, but when he realised he could not achieve a compromise with the republicans he decided there was no alternative to a military showdown.
One of the characteristics of Collins was his decisiveness once he had resolved to take a particular course. If that meant turning a blind eye to the involvement of British soldiers, he may well have decided it was a price worth paying.
THE last thing the National Army and the provisional government needed in 1922 was a half-hearted or less than successful defeat of the Republicans in the Four Courts as this would have been a disastrous start to a civil war the National Army needed to win quickly and emphatically.
Facing a bombardment that could not be resisted, the Four Courts' occupants surrendered two days later.
It is well known that the provisional government accepted the British offer of military equipment to boost its civil war effort, but Creek's memoir suggests there was more to it.
It is also a reminder of the considerable power that Britain still had over Irish affairs, with the explicit threat of intervention in Ireland in the air.
Creek's version cannot be accepted as the definitive truth -- no single document or memoir can. But its uncovering is a reminder that, during this decade of centenaries of the events of the Irish revolution, we will be offered new perspectives, new revelations and voices from the archives that suggest fresh interpretations of seminal and controversial events that took place during this period.
Diarmaid Ferriter is Professor of Modern Irish History at UCD. His new book 'Ambiguous Republic' is published this week