’New’ document by Eugene Downing

Paddy O’Daire and the Thetis Experiment: Setting the record straight

Letter to Saothar, journal of the Irish labour History Society, 18, 1993, with 2 replies.


While reading Román Brindley’s interesting piece on Paddy O’Daire in Saothar 17, I was very surprised to see a repetition on the fiction about the four Irish International Brigaders who are supposed to have taken part in the tests carried out by Professor Haldane in connection with the Thetis submarine disaster in 1939. Saothar has a very high reputation for accuracy and attention to detail in its historical research and for quoting meticulously from original sources of information.

The records of the period show that Paddy Duff of Dublin was the only Irish International Brigader involved in the experiments. The other three Brigaders were British – Bill Alexander, Don Renton and George Ives. The first edition of the Daily Worker, dated 21 July 1939, contains a report and a picture of Professor Haldane and the four Brigaders involved. Ronald Clark’s biography of Professor Haldane gives full details and a picture of three of the participants with Professor Haldane.

Even if these sources didn’t exist, I would still be aware of the facts as I was in London at the time and knew all the participants. Indeed, when Professor Haldane was looking for volunteers to take part in these very dangerous experiments, I can claim the distinction of being the very first not to volunteer!

When Paddy Duff died in April 1972, the late Michael McInerney wrote his obituary in the Irish Times. As he explained to me shortly before his own death in January 1980, he wrote under pressure and from memory thus getting the names wrong when dealing with the Thesis incident. Subsequent writers on the subject, instead of doing their own research, simply copied Michael.

Eugene Downing

County Wicklow.


Eugene Downing is correct when he says that Paddy O’Daire was not involved in Haldane’s Thetis experiment. But he was involved in another submarine experiment in the following year. As far as the Thetis was concerned, it was, as Downing says, Alexander, Duff, Ives and Renton who joined Professor Haldane in a ‘courageous attempt to provide evidence for the Thetis Inquiry’ by submitting ‘themselves to a test which involved severe carbon dioxide poisoning’(Daily Worker, 21 July, 1939.)

While Haldane’s formal evidence is carried on the front page under the banner ‘J B S Haldane and Four Spain Brigaders in Thetis Test Ordeal’, elsewhere the Daily Worker gives the volunteers’ account. Don Renton was described as ‘now well known as a leader of the London Unemployed’; George Ives identified as having ‘spent a considerable time in a Franco concentration camp’; Bill Alexander honoured as having been ‘prominent in the British Battalion’; while Paddy Duff was simply ’also of the British Battalion’.

The men described their experience quite graphically: “We entered the chamber at 2.40pm and were sealed in. The air pressure was raised and then Professor Haldane let nitrogen and carbon dioxide in to make the air foul. The chamber was about six feet in height and six feet wide. We were sitting shoulder to shoulder and there was only enough room for Professor Haldane to move and adjust the controls”. They were soon “hot and gasping…and laughing continually at small incidents”. Duff said he was “panting as if I had run a mile” and he “developed a terrible headache”. After release from the chamber they were immediately fitted with Davis rescue apparatus which made them sick and Alexander tore his suit off. While providing valuable information, whether the Thetis men might have escaped remained a ‘matter for conjecture.’

According to Ronald Clark’s biography of Haldane, the professor was asked by the admiralty in March, 1940, to investigate how men might escape from a sunken submarine.(1) Recalling the Thetis experiments, Haldane approached the Communist Party for people to take part in fresh tests. Four IBers were proposed – a merchant seaman, a machinist, a tailor and a man who by this time was serving in the British Army. According to Bill Alexander (2), those involved in the later experiment were all Irish – Duff, Larmour, Prendergast and Paddy O’Daire. Alexander, incidentally, says that the mistake in the original Saothar piece on O’Daire is that he was never Chief of Operations of the XVth International Brigade! He was, however, involved in the bravery and valour of the Thetis experiments, albeit not the original one.

George Matthews,

Communist Party Library, Picture Library and Archive



R Clark, JBS: The Life and Work of J B S Haldane, London, 1968. An account of the Thetis experiment is contained on pp 135-148. (2)

Bill Alexander, Secretary International Brigade Association, said that “Haldane published a scientific paper, ‘After Effects of Exposure of Men to Carbon Dioxide’ in the Lancet, 19 August, 1939, pp 419-22, a copy of which he sent to all the volunteers.”

Dear Comrades

Eugene Downing is right as far as the first Thetis experiments are concerned. I recall Paddy O’Daire telling me that he was involved in a later experiment with Jim Prendergast, John Larmour and Paddy Duff – Duff’s second time.

Incidentally, Paddy O’Daire was at no time ‘Director of Operations of the XVth Brigade’. He was at the ‘Higher Military School’ for a period on the recommendation of Frank Ryan but Paddy did not remain there, preferring to go to the front.

Jack Jones

TGWU Retired Members’ Association