None, because racism will always exist in society at large; there will always be somebody who is racist,though racism diminishes. One senior officer said, on Radio 5, that the majority of very recent complaints where action was being taken had been instigated by colleagues of the person reported, which is encouraging (but he didn't say how many of those reporting were themselves black, which would have strengthened his claim). And he only cited 10 complaints !
That any officer is the subject of racism 'charges', is itself miraculous to me, who knew the Met of 40 years ago. Not only was racism not being pursued in disciplinary proceedings, it was casually accepted and not recognised as anything out of the ordinary. That's because it wasn't 'out of the ordinary'. It wasn't so long ago that 'institutional racism' was first mentioned in a report on the Met, after all.