When Lewes Borough Bonfire Society parades on Saturday night at one of Britain’s biggest bonfire festivals, all eyes will turn to a group dressed as Zulu warriors who for decades have painted their faces black but finally agreed on Friday to stop after an anti-racism campaign.

Preparations for the riotous celebrations that date back to the 17th century have been tense after black and mixed heritage residents in the East Sussex town insisted the practice was racist and “shockingly offensive” and rallied opposition in a 1,600-signature petition.

The response had been blunt from some of the “bonfire boys”. “Keep calm and black up for bonfire,” read the slogan on one Facebook page. They insist it is tradition – supposedly a show of respect for the bravery of Zulu warriors – and not racism. They have reacted with characteristic Lewes contrarianism invoking a Sussex saying: “We wunt be druv” (“We will not be driven.”)

But for the first time in generations the black facepaint may stay unused because of the intervention of the leader of a Zulu dance troupe from South Africa who had been invited to join the procession.

Thanda Gumede, the troupe’s leader, delivered an ultimatum: drop the black face or we won’t come. After delicate negotiations the bonfire society agreed and said it would also remove skulls, nose rings and dead monkeys from its costumes that Gumede, from Durban but living in Leeds, said were a “gross misrepresentation and unacceptable stereotype of Zulu and black people at large”.

Local black residents also argued the black facepaint was “shockingly offensive on impact” and “condones the negative stereotyping of people of colour”.

Mick Symes, a bonfire society committee member, told Gumede: “Our committee has accepted in full your guidance and will be instructing our members to try and achieve as much as is possible in the time available.”

When his troupe, Zulu Tradition, was first booked Gumede had only seen one image of the bonfire society costumes and did not consider it offensive, but after further research he changed his mind.

One of the local campaign leaders against the blacking up described it as “shockingly offensive on impact” and said it “condones the negative stereotyping of people of colour”.

The row has drawn attention to the intense and sometimes insular bonfire culture of Lewes, which has existed since the 17th century and channels the town’s history of non-conformism and anti-Catholicism and love of ridiculing the powerful and staging a raucous party.

The Borough society, whose members have been dressing as Zulus since at least the second world war, is one of six societies that parade with an array of effigies and costumes, before marching to separate bonfire sites to torch their centrepiece – huge models of political figures which have included Donald Trump, David Cameron holding a pig’s head, and Vladimir Putin.

An effigy depicts David Cameron during the 2015 bonfire night celebrations in Lewes. Photograph: Ben Stansall/AFP/Getty Images

Members of different societies come as native Americans, Vikings, monks, smugglers, Tudors, French revolutionaries and colonial soldiers. One society parades with 17 burning crosses to commemorate the protestant martyrs executed in Lewes in the 16th century.

An effigy of Pope Paul V (d1621) is burnt by Cliffe Society and all the while torches and barrels burn and “rookies”, powerful agricultural bird scarers, are detonated in packed streets as rum, mead and the local Harvey’s ale flows. Eighty people were injured last year.

But bonfire is no niche pursuit. It is estimated that some 6,000 people are members of one of the societies.

“It is part of the DNA of the town,” said Graham Mayhew, four-time mayor of Lewes. “You are expected to support bonfire. If there are rows, whole families have been known to uproot from one society to another. It’s a clan thing.”

Perhaps the fastest-growing society is Southover, which is known as the most middle class and preferred by incomers, known caustically in Lewes as DFLs – down from London.

Applications are vetted by committees and members can be thrown out for infractions such as using rookies that are too powerful, or going on social media to criticise other societies, one insider said.

One London exile who is a member of Southover said: “I am a massive fan. It runs through the fabric of the town and binds the community together.”

The bonfire season runs from September to December and the societies run a string of events from torch making to summer camps and fundraising dinners.

While the pope burning suggests Northern Irish-style communal tensions, locals stress that is in the past.

In 1981 Rev Ian Paisley came from Northern Ireland to whip up Protestant hate, according to Mayhew.

“It went nowhere,” the then mayor said. “Everyone was embarrassed because they had long since lost any feeling for that sort of thing.” Next year they burned an effigy of Paisley.

Speaking about the bonfire society’s decision to stop the blacking up, Gumede said: “I am really excited by this, and it is good to know I can play a part in changing things that have been in place since world war two.”

But Symes conceded that with 70 people planning to dress as Zulus - including some from families that have done so for three generations - some members may not comply.

“I am not going to give a guarantee there will be no ‘blackface’ around,” he said. “But the guarantee I can give is we are bending over backwards to comply with this advice.”