The BBC showed "basic" journalistic failures in a news report in which it wrongly accused a senior politician of child abuse, an internal investigation has found. The findings were announced after the BBC's acting director-general, Tim Davie, pledged to "get a grip" of the deepening crisis at the world's largest publicly-funded broadcaster as two more top news executives stood aside. The investigation into the allegations that a former Conservative party treasurer, Alistair McAlpine, had abused children at a home in Wales in the 1970s found there had been a failure to complete "basic journalistic checks". The report by the BBC's Scotland director, Ken MacQuarrie, found that journalists on the flagship Newsnight programme which broadcast the claims had failed to show the politician's accuser a photograph of McAlpine. These failings were "unacceptable", MacQuarrie said. He also highlighted confusion about who had the ultimate responsibility for "final editorial sign-off" on the story, which the BBC had to retract after it was shown. Newsnight 's editorial management structure had been "seriously weakened" because the editor had stepped aside over the decision last year to shelve a story about star BBC presenter Jimmy Savile's sexual abuse of children. George Entwistle stepped down as the BBC's director-general on Saturday after the botched Newsnight report and the BBC's response to the Savile scandal. On Monday, head of news Helen Boaden and her deputy, Stephen Mitchell, were asked to stand aside pending an internal review into the way that the claims against Savile were handled by Newsnight . Davie, handed control of the BBC after just seven years at the organisation, said his job was to restore leadership following Entwistle's sudden resignation. London mayor Boris Johnson called for the "wholesale massacre of everybody involved - professionally speaking". He told ITV1's The Agenda programme that there had been "an absolutely catastrophic breakdown of journalistic standards" at Newsnight .