The family of the black boy rammed off his pedal cycle by police who mistook his water pistol for a real gun have won their fight to have an independent investigation into the incident launched. The Independent Office for Police Conduct (IOPC) on Friday reversed a decision it had made twice to let the Metropolitan police investigate the actions of its own officers. The reversal followed two days of publicity about the case, after it was first revealed, and on Thursday the London mayor, Sadiq Khan, asked the IOPC to investigate. The IOPC’s repeated refusal frustrated the family, and their solicitor, Raju Bhatt, described the watchdog as “shameless tossers” after the U-turn was announced. The incident in July in Hackney, east London, left the 13-year-old boy suffering trauma, and he is still having nightmares. He was playing near his home with a blue water pistol, while his sister had a similar toy in pink. A passing officer thought the toy was real, and armed police who arrived used their vehicle to knock the boy off his bike before handcuffing him and pointing their guns at him. He was de-arrested shortly after his mother intervened and officers carrying submachine guns realised he had just been playing with a toy water pistol on a summer’s day. His family twice asked the police watchdog, which is struggling to earn community confidence, to investigate – and on the second occasion included the specific allegation that racial bias may have played a part in the police actions. Catriona McGregor, a solicitor for the boy and his family, said: “It is very telling that the IOPC were not able or willing to do their job in relation to the case of Child X until they were brought under the spotlight of national news coverage on the case. “Now that they have been compelled to accept their responsibility for the investigation of this matter, our client – the mother of Child X – looks to them to ensure that their investigation is as thorough and rigorous as possible, examining all aspects of her complaint including the obvious role that race played in the way she and her son were treated by the police.” The Met has apologised but says so far no misconduct issues have been identified. The IOPC regional director for London, Charmaine Arbouin, said on Friday: “We were also confident, and remain confident, that the Met were taking the complaint seriously.” She added: “In the light of the mother’s statement yesterday, and the concerns that have been expressed by the local community in Hackney and more widely, we’ve reconsidered our decision and will now investigate this independently.” Arbouin also said resources were a factor, as was the watchdog’s belief that the family wanted a speedy resolution. One issue the IOPC will have to decide on is whether disciplinary notices are issued to the firearms officers involved. More than 100 recently refused to carry their weapons after a separate case.