Police have been brought in to investigate allegations that black players in Chelsea’s youth system during the 1980s and 1990s were subjected to a “racist bullying culture” from members of staff.

Detectives from the child-abuse investigation team at Northwood police station in north-west London are looking into a complaint that one of the teenage footballers on Chelsea’s books was the victim of assault during the years when black players as young as 11 allegedly had to endure harrowing racial abuse.

“Police received an allegation of non-recent racially aggravated assault in September 2018,” a spokesman for the Metropolitan police said. “Inquiries are ongoing.”

At least two former players have been interviewed and it is also understood the police have spoken to one former staff member. “There have been no arrests,” the police spokesman said. “We do not confirm who we have spoken to as part of an investigation.”

The news of the police being involved comes at a difficult time for Chelsea; four supporters have been suspended from Stamford Bridge because of the abuse directed at Raheem Sterling during Manchester City’s visit two weekends ago. A number of Chelsea fans could be heard chanting an antisemitic song during their Europa League tie against Vidi in Budapest last week and the club released a statement to describe it as abhorrent and condemn “any individuals that can’t summon the brainpower to comprehend this simple message”.