Britain sent ‘banned’ gas grenades to Ireland to counter anti-Treaty rebels, files reveal

More than 1,000 poison gas grenades were sent to Dublin to aid the Provisional Government in 1922

Six days after the Irish Civil War began, the British cabinet considered an extraordinary request from the Provisional Irish Government in Dublin.

The request had come while the Provisional Government was using British field guns to remove the anti-Treaty rebels from the Four Courts, the attack which started the war.

On July 4th, 1922, the missive from Dublin was read to stunned cabinet members. A British cabinet minute, which was revealed in a documentary on the Civil War by Michael Portillo earlier this year, stated: “The cabinet was informed that the Irish Free State government had intimated that if they could be supplied with some kind of gas grenades, the task of clearing the rebels out of the Four Courts would be greatly simplified.”

The British government responded by pointing out that the UK was a signatory to the recently ratified Washington treaty on noxious gases.


It stated that a ban on poison gas, which killed so many soldiers in the first World War, shall be “universally accepted as a part of international law binding alike the conscience and practice of nations”.

The Washington treaty was a response to the universal revulsion at the use of poison gas during the first World War which started with the Germans, but was quickly adopted by all sides. It would therefore be “improper” to hand over gas canisters, the cabinet concluded.

Officially that would appear to have been that, but unofficially it wasn’t. That memo may have been for the cabinet record, but further digging by the team at Midas Productions who made the Portillo documentary revealed the opposite had occurred. In secret the British had sent the poison gas grenades to Dublin post haste.

Researchers Lydia Monin and Andrew Gallimore found the documents during a trawl of the UK National Archives in Kew.

A huge cachet of gas grenades, 1,008 in total, were sent on their way that evening in a special train to Holyhead where a torpedo boat was waiting to take them to Dublin. By the evening of July 5th, the grenades were in the possession of General Sir Nevil Macready, the officer commanding the remaining British troops garrisoned in Ireland.

He did not inform the Provisional Government about it and he opted to keep them as a contingency only to be used in extremis. Though Macready was no lover of the Irish, he had persuaded the British government not to act rashly following the outrage surrounding the assassination of Field Marshal Sir Henry Wilson MP on June 22nd, 1922.

The consignment were known as SK grenades after South Kensington where they were developed. They contained liquid ethyl iodoacetate, a lachrymatory (tear) gas that had been first used by the British at the Battle of Loos in 1915 to clear German trenches. They were also deadly at certain concentrations and banned by the Washington treaty.

While Macready kept possession of them, cabinet officials debated the legality of using the grenades. On July 8th they came to the conclusion that they were banned from being used in wars.

However, the definition of war, in this case, only meant a conflict between two sovereign states. Therefore, “what is going on in Dublin is not war within the meaning of this provision ... the article certainly provides no bar to the use of the consignment in questions in Ireland”.

Nevertheless, the secretary of state for war, Laming Worthington-Evans, a signatory of the Anglo-Irish Treaty, was alarmed by the prospect of these grenades being used. On July 10th he drafted a memo for the British cabinet stating that if these grenades were banned from use in war, “its use is all the more to be condemned in peace between people who are not at war with each other”.

Luckily for both governments, the gas grenades proved to be unnecessary. The Provisional Government was able to remove the rebels from the Four Courts and from the city of Dublin using conventional artillery. Free State forces also captured the cities of Limerick and Cork without recourse to drastic measures.

Had they been used, they would likely have disgraced the Provisional Government and its British counterparts in the eyes of the world.

What happened to the gas grenades? That’s a mystery that remains to be solved. Most likely Macready would have ordered them to be buried at sea. They may now be somewhere at the bottom of the Irish Sea.

The British cabinet memos will be the subject of a new RTÉ podcast to be presented by David McCullagh which will be broadcast later this summer entitled Taking Sides: The Poison Gas Files.

Ronan McGreevy

Ronan McGreevy

Ronan McGreevy is a news reporter with The Irish Times