Between 1935 and 1974 a range of chemical and electrical experiments were carried out on homosexual men in psychiatric institutions. “Aversion therapy” was intended to alter sexual orientation and was based on the notion that sexual preference was a choice and not innate. “How it was presented to us was that these behaviours were deviancies ... an adoption of a lifestyle that you chose,” recalls one of the 17 retired mental health nurses interviewed by Tommy Dickinson for his book. The interviewees (eight male and nine female, aged from 63 to 98) had administered aversion therapy as instructed by the consultants under whom they worked. Dickinson, a historian of nursing, has written his detailed study as an attempt to access the thoughts and feelings of ordinary men and women who were asked to carry out procedures many of them believed to be barbaric.

He also interviewed eight men who had undergone the therapy. All but one of these former patients had self-referred, having approached their GPs in the hope that they could be “cured” and made heterosexual. Just one man in Dickinson’s survey had arrived via the alternative route – agreeing to treatment in order to avoid prison, following a conviction for engaging in homosexual activity. (This was the lethal trade-off offered to Alan Turing in 1952 – oestrogen injections or jail.)

So aversion therapy was not carried out against patients’ wishes, but as Dickinson points out, their choices were hugely compromised. Not one of the GPs cited by the interviewees had suggested anything other than aversion therapy, while having to choose between prison and treatment scarcely qualifies as consent.

He cites psychiatrist Louis Max as the first to have used the treatment in the UK, in 1935. Subsequently, the removal of all norms during the second world war seemed to promise new possibilities for stepping outside traditional gender identities and sexual behaviour. But “the horrors of peace were many”, as Quentin Crisp would later write; the family and domesticity were revered in the late 1940s and 50s. Aversion therapy was deemed to have had positive results on alcoholics: its use on homosexuals, transvestites and fetishists was now stepped up. Dickinson writes that “homosexual men were seen to be a contagious risk, who undermined postwar social reconstruction by turning their backs on family life”.

Dickinson is careful not to take the easy (and anachronistic) approach of attacking one era for not sharing the ethics of our own. However, he reveals that by the mid-1950s there were a number of dissenting voices opposing the sexual conservatism of the age: psychiatrist Dr Walter Lindesay Neustatter pointed out that while we may know what is “customary”, we cannot state what is “normal” with regard to desire. The Church of England itself, as early as 1954, called for the legalisation of sex between consenting males over 21. The Sunday Times sought a public inquiry, since the law on homosexuality was “not in accord with public opinion”. The Wolfenden report of 1957 favoured decriminalisation, but the law in England and Wales remained unchanged until 1967. The following seven years saw the gradual petering out of aversion therapy for homosexuality in the UK.

The influence of popular and highbrow culture on nurses emerges from the testimonies given to Dickinson. In the 1950s, both tabloid and broadsheet newspapers carried reports of how science was now able to cure the “illness” that was homosexuality. Such journalism allowed some hospital staff to feel that they were being cruel to be kind – that aversion therapy would put an end to the psychic agonies endured by the men who presented themselves for treatment. However, newspaper stories could also help nurses to empathise fully with their patients, as did novels and, later, films. Rodney Garland’s 50s novel The Heart in Exile, for example, brought one female nurse “an understanding of the challenges homosexual men face. I never realised how difficult it must have been for them”. Given no ethical guidance in their training or workplace, many of the nurses found that it was culture that helped them establish for themselves why what they were being asked to do was wrong.

What were they being asked to do? In chemical therapy, an emetic was injected by the nurse, and as nausea took hold, the subject was given pictures of an unclothed or barely clothed male. In some hospitals, the patient was confined to his room and left surrounded by his vomit, his latrine bucket unemptied too, so that the link could be forged in his subconscious between his sexual preference and physical squalor. One variant added torment by tape recorder: a consultant recorded statements of how disgusting the patient and his sexuality were, and the tape was played as the emetic began to take effect. The same consultant asked the nurses to wake the patient every two hours and play another tape, in which the benefits of having a wife or girlfriend were intoned. This could go on for three days and nights.

With electrical aversive techniques, electrodes were placed on wrists, calves and feet, and shocks administered when a picture of an unclothed male was displayed, or when the subject was asked to fantasise about a male. Alternatively, the entire floor would be covered with an electric grid, with the current passing through the feet when arousal was detected. In both types of treatment, it was thought that sleep deprivation and provoking emotional crises made subjects more easily persuadable.

Does it even need to be said that none of Dickinson’s interviewees became heterosexual? Many patients were shattered by the process, though. One told Dickinson: “I think three days [of treatment] has destroyed 25 years.”

The hierarchical nature of hospitals meant that objecting to aversion therapy, or refusing to carry out tasks related to it, would result in dismissal. All that was available to nursing staff was subversion, and one of Dickinson’s female interviewees confessed to only pretending to have given the emetic injections, and instead sitting down to chat to the patient, unseen by other staff. In the late 60s, a female nurse agreed to go on a “date” with a patient (as advised by a consultant), and the pair spent the evening laughing at the whole stupid, sorry story of aversion therapy.

There are also tales of colleagues who appeared to enjoy the brutality of the procedures (“you could just tell they did”), as well as the paradox of homosexual nurses having to administer aversion therapy. One of the latter stated that there was no contradiction or hypocrisy involved, since “all of these men were willing to try or do anything to make them straight. Although my experience of being gay was very different, I suppose I just thought: ‘I’ve got to help them’.” However, the same nurse also pointed out that objecting would have led to dismissal, and it is this tangle of motivations, self-justification and self-blame that is at the heart of Dickinson’s powerful and moving book.

It is not a smooth, elegant or jargon-free read, but since ‘Curing Queers’ isn’t a book aimed at the general reader, it would probably be unfair to expect it to be so. Dickinson blends the personal testimonies with a helpful synthesis of much recent outstanding work in “queerstory”. He also generously points the reader in the direction of further documentary sources on this peculiarly nasty episode in recent British history.

• Sarah Wise’s Inconvenient People is published by Vintage. Curing Queers is published by Manchester University Press (hardback £70; Kindle £15.60). manchesteruniversitypress.co.uk.