Just after the Easter Rising finished and the executions started, The Irish Times prophesised that the rebellion would "pass into history with the equally unsuccessful insurrections of the past".

What would have happened had the British not executed the leaders of the Rising is one of the great imponderables of history. Would the mood of anger and dismay at the destruction and loss of life have remained?

Would the hostility towards the rebels evident on the streets of Dublin after the rebellion have persisted if they had not been executed?

Veteran Nationalist MP John Dillon was sure, even while the executions were going on, that they were “letting loose a river of blood”. It was the first time the British had the bulk of the Irish population on their side in a rebellion, he told the British prime minister Herbert Asquith, yet the executions had changed all that.

Disastrous aftermath

The blame for the disastrous aftermath of the Easter Rising lies firstly with Gen John Maxwell, who was given “plenary powers” to deal with the rebels as he saw fit.

The British government effectively washed its hands of responsibility. What demanded a carefully calibrated political response was dealt with instead by the brutal instrument of martial justice.

The British used war-time regulations to deal with the rebels. The dreaded Defence of the Realm Act was invoked to stymie anything regarded as injurious to the British war effort. Those involved with the so-called mosquito press or those making anti-recruitment speeches were dealt with by the Act.

Crucially, it allowed those regarded as having assisted the enemy to be tried by field court martial. It involved three army officers, irrespective of whether or not they had legal training.

Affront to justice

Those British officers chosen to have the power of life or death over the rebels were chosen simply because they were available.

Even by the standards of the day, the executions were an affront to justice. They were held in secret, the accused were allowed no defence and the executions were carried out without leave to appeal.

It is clear from the paucity of documentations surrounding them, and the sheer volume of trials processed, that they were designed with only one outcome in mind – the execution of the rebels involved.

Many of the leaders, most notably Patrick Pearse and Seán MacDiarmada expected to be executed and, indeed, sought it. They had, after all, invoked the aid of Britain's mortal enemy, Germany.

But there were also precedents from another part of the British empire which suggested a more judicious process might have been appropriate.

In late 1914, Gen Louis Botha’s Union of South Africa faced an internal revolt from his fellow countrymen who had aligned themselves with Germany. The revolt was suppressed but none of the leaders were executed lest they create martyrs for the cause.

The Irish Parliamentary Party leader John Redmond and his deputy John Dillon invoked the Botha example, but they had reckoned without the bovine stupidity of Maxwell, who was given a free hand to do what he saw fit.

Historic mistake

In the end, he ordered 15 men to be executed and commuted the other sentences.

By the time Asquith had arrived in Dublin just after the last executions, the damage had been done. Britain had made a historic mistake. As George Bernard Shaw said afterwards: “It is absolutely impossible to slaughter a man in this position without making him a martyr and a hero, even though the day before the rising he may have been only a minor poet.

“The shot Irishmen will now take their places beside Emmet and the Manchester Martyrs in Ireland and beside the heroes of Poland and Serbia and Belgium in Europe, and nothing in heaven or on earth can prevent it.”