Nigel Farage’s claim that accusations of racist and antisemitic behaviour from his schooldays are motivated by hostility to his politics is facing mounting challenge, after multiple former classmates came forward with detailed and largely apolitical accounts of his conduct at Dulwich College in the late 1970s and early 1980s.

The Reform UK leader has repeatedly argued in recent days that there is a “strong political element” to the reports and that those speaking out against him do so because they oppose his views and his party. At a Reform UK press conference this week, he suggested that only one former pupil, the film-maker Peter Ettedgui, had alleged direct abuse, and that others were essentially objecting to his politics.

However, a series of investigations, led by the Guardian and based on interviews with around 20 contemporaries, paints a more complex picture. Former pupils and a former teacher have described what they say was repeated racist and antisemitic behaviour by Farage as a teenager, ranging from Nazi salutes and chants to personalised slurs directed at individual classmates.

Farage, 61, has denied being racist and dismisses the accounts as either exaggerated or misinterpreted through “the modern light of day”. In broadcast interviews this week he said he would “never, ever” have racially abused anyone in a deliberately “hurtful or insulting way”, insisted he had never “directly racially abused anybody… not with intent”, and characterised any offensive language as “banter in a playground” nearly half a century ago.

The allegations centre on Farage’s time at Dulwich College in south London. Former pupils, some named and some anonymous, have told reporters that he led or taught a racist chant known as “Gas ’em all” on Combined Cadet Force coach trips, with lyrics about gassing Black, Jewish and Asian people. Others recall what they describe as enthusiastic Nazi salutes, shouts of “Sieg heil” and comments such as “Hitler was right”.

Several accounts focus specifically on Ettedgui, a Jewish former pupil who has put his name to his testimony. He alleges that Farage approached him repeatedly to say “Hitler was right” and “gas them”, sometimes, he says, adding a hissing sound to imitate gas chambers. Farage strongly denies this and says he has “never tried to hurt anybody”.

Farage’s assertion that Ettedgui is the only person claiming direct abuse is not borne out by the reporting to date. Another former pupil, Cyrus Oshidar, of South Asian heritage, says Farage repeatedly used a racial slur towards him. An unnamed classmate from a minority background has alleged that Farage, flanked by taller friends, would approach pupils who looked “different”, ask where they were from and then point away saying that was “the way back” to that country, something he says happened to him three times.

In addition, at least seven other former pupils told the Guardian they either witnessed or were subjected to antisemitic targeting of Ettedgui. They include Stefan Benarroch, who says Farage made Ettedgui’s life “a nightmare”; Rickard Berg, who recalls Farage singing the “Gas ’em all” song at Ettedgui; Anthony Butler, who alleges “relentless” bullying using a slur for Jews; and Jean‑Pierre Lihou, who says Farage addressed Ettedgui as “Jude” in what he describes as a menacing, 1930s‑style tone. A former teacher, Bob Jope, has said he believes he once heard Farage tell Ettedgui to “shut up” using a reference to his being Jewish.

Farage has also suggested that those speaking out are political opponents, citing their supposed dislike of Reform UK. But according to the paper’s reporting, the overwhelming majority of the roughly 20 people interviewed are not active in party politics. Only one, Martin Rosell, is currently a local chair of the Liberal Democrats. Others describe themselves as non‑aligned or politically disengaged, and say their decision to speak publicly was prompted by Farage’s growing prominence and by what they see as increasingly categorical denials of behaviour they remember.

Farage has also pointed to Roger Gough, a former Conservative leader of Kent county council, as evidence of politically motivated criticism. But Gough is not among the witnesses or alleged victims in the latest reporting; his past comments related to concern within Dulwich College in 1981, when a teacher wrote to the headmaster warning against appointing Farage as a prefect because of what the teacher described as publicly professed racist and “fascist/neo‑fascist” views.

That letter, which resurfaced in 2013, referred to a classroom incident in which Farage was said to have been so offensive towards another boy that he had to be removed, and to a cadet camp march where he and others allegedly shouted Hitler Youth songs. Farage has previously told interviewers he said “ridiculous things” as a schoolboy but has disputed being racist and denied being excluded from lessons for such behaviour.

The latest controversy has prompted a political response at the highest level. Prime minister Sir Keir Starmer has called the allegations “disturbing” and urged Farage to “explain himself” and apologise to those who say they were targeted. The government’s independent adviser on antisemitism, Lord Mann, has condemned Farage’s attempt to describe the alleged conduct as playground “banter”, calling on him to come clean and express remorse.

Farage has so far resisted demands for an apology, instead stressing the passage of time and insisting that his teenage behaviour is being weaponised for partisan reasons. With further testimonies emerging and his own characterisation of the allegations under direct challenge from those who shared a school with him, pressure is likely to intensify on the Reform UK leader to offer a fuller account of what happened – and whether he believes any of it now warrants contrition.