Boris Johnson’s former race adviser has warned of another Stephen Lawrence or Jo Cox tragedy if members of the government continue to inflame the culture wars gripping parts of the nation.

Speaking publicly for the first time since he resigned two months ago, Samuel Kasumu said he feared there were some in government pursuing a strategy of exploiting division for electoral gain that could result in severe consequences for the country.

“There are some people in the government who feel like the right way to win is to pick a fight on the culture war and to exploit division,” he told the Guardian in an interview. “I worry about that. It seems like people have very short memories, and they’ve already forgotten Jo Cox.”

The man who killed her, he believes, was potentially radicalised and worked into a “frenzy” by the culture war narratives in certain newspapers and pushed by media commentators.

“If I was going to go to William Hill today and place a bet on what the most likely option is, I’d probably say a Jo Cox, a Stephen Lawrence, a Windrush scandal is where we’re headed if you don’t find a way to overcome this cultural moment. I feel like the government must be the ones to try to help drive that change.”

Kasumu’s stark intervention follows the leaking of his resignation letter in February, which accused the Conservatives of pursuing a “politics steeped in division”. He was persuaded to remain in place by Nadhim Zahawi, the vaccines minister, to continue his work on overcoming hesitancy to the Covid-19 jab among certain communities.

The resignation named Kemi Badenoch, the equalities minister, and noted she may have broken the ministerial code when she accused a young, black journalist, Nadine White, then working for HuffPost, of “creepy and bizarre” behaviour in a Twitter thread for asking questions about a Covid vaccines video. The journalist received a torrent of abuse as a result, according to her employer, and led to an alert about the risk to media freedom being registered with the Council of Europe.

“There’s an assumption that I have issues with Kemi. I don’t have any personal issues with her,” Kasumu said. “But when that happened, a lot of things went through my mind. I thought to myself, if that young journalist was my sister, or relative of mine, how would I feel about a minister responding to her in such a way?

“I thought, if the journalist was Andrew Neil, or Laura Kuenssberg, or Robert Peston, would the minister have responded in the same way? Were the minister’s actions distracting people from very important public health messages? It just led me to the conclusion that it was completely unacceptable.”

In April, Kasumu resigned in the middle of the furore of the government’s racial disparity report, which drew sharp criticism from a range of individuals, including Simon Woolley and Doreen Lawrence, who said it would allow racism to flourish.

Kasumu refused to be drawn into controversy around the report, though he did tweet that he had “so many emotions” reading the report and that he was in “total shock”.

He acknowledged he was the point man for the commission when it was first announced and was heavily involved in the recruitment of commissioners.

He said Tony Sewell’s appointment as chairman of the commission drew backlash, but he insists he should have been on the commission, describing him as a good man who has helped change the life direction of thousands of young people. He also said he told colleagues that they owed Sewell a duty of care to protect him.

He also described the prime minister, Boris Johnson, as a liberally minded individual and said there was a disconnect between Johnson and what people have coined as “Johnsonism”. “When I think about my interactions with the prime minister, he was always very supportive about things that I wanted to do. And I would actually go further and say that he was often more keen for me to go further, to be even more ambitious.”

A No 10 spokesperson said: “The entirety of the UK government is focused on defeating this pandemic and building back fairer for everyone. That is our priority.

“The minister for women and equalities clearly set out in her ‘fight for fairness’ speech the government’s plans for an evidence-based equality agenda in the UK.

“This includes racial equality, which is why the prime minister set up the Commission on Race and Ethnic Disparities and, following their detailed report, the government will shortly respond to their recommendations”.