Keir Starmer has said he will sign up for unconscious bias training amid criticism of his response to Black Lives Matter protests and calls from a new co-chair of Momentum to “get Labour’s house in order” over racism. The Labour leader said the training was being introduced “for all of our staff and I’m going to lead from the top on this and do that training first”. He added: “I think everybody should have unconscious bias training. I think it is important. There is always the risk of unconscious bias and just saying ‘oh well it probably applies to other people, not me’ is not the right thing to do.” During an appearance by Starmer on LBC on Monday morning, a caller challenged him for describing the Black Lives Matter (BLM) movement as a “moment” during a BBC Breakfast interview a week ago. That turn of phrase, and his dismissal in the same interview of calls to “defund the police” and divert the money elsewhere as “nonsense”, led to accusations that Starmer was belittling the grievances of anti-racism campaigners. Starmer insisted he had been misunderstood, telling the LBC caller: “What I was saying last week is that Black Lives Matter needs to be a moment, and I meant a defining moment and a turning point. I didn’t mean a fleeting moment.” A wider row in Labour has been fuelled by a leaked report on antisemitism that revealed WhatsApp conversations between party staffers including hostile comments about black shadow ministers under Starmer’s predecessor, Jeremy Corbyn. The reported messages included ones describing Diane Abbott, then shadow home secretary, as “truly repulsive” and a “very angry woman” – a phrase critics said invokes a racist trope. Staff commented negatively on Dawn Butler’s appointment to the shadow cabinet, appearing to suggest her accusations of racism within Labour were untrue. Clive Lewis, the shadow business secretary, was also insulted. The former shadow chancellor John McDonnell wrote in an article for the Guardian shortly after the leak: “The alleged abuse of Diane Abbott, Dawn Butler and Clive Lewis, three prominent black shadow ministers, was appalling and, as others have commented, betrayed a deeply worrying underlying strain of racism.” The party has appointed a panel to investigate the content of the report and the leaking of it, and Starmer has said he will not comment on it until the results are in. Last month journalists at OpenDemocracy covering the story received a response from Labour describing criticism of the WhatsApp comments as “po-faced” and saying their tone reflected the expectation that they would remain “private and confidential”. Amid anecdotal suggestions that Labour is losing the support of black and other minority ethnic communities, Starmer held a “black reporter-only” press briefing last week in which he appealed to black voters not to leave the party. On Monday one of the new co-chairs of Momentum, Gaya Sriskanthan, said of Starmer’s response to the criticism that “taking a knee is not enough”, a reference to when the Labour leader was photographed kneeling in solidarity with those opposing anti-black racism. Sriskanthan, a climate activist, and Andrew Scattergood, a firefighter, were elected over the weekend to lead the grassroots movement, jointly taking on the role previously held by Jon Lansman. Sriskanthan said: “It’s a tragedy that so many BAME people are leaving Labour and Keir must deal swiftly with the racism revealed by the leaked report and get Labour’s house in order. “Momentum will do everything it can to make Labour a friend of social movements and welcoming for BAME people. Our party must reach out and work in earnest with the Black Lives Matter movement, not criticise it.” The Labour party has been contacted for comment.