indeed the met cases are more serious as its about corruption rather than budgets or incompetence - the IPCC are investigating the following
https://www.ipcc.gov.uk/news/ipcc-i...tion-relating-child-sexual-abuse-metropolitan
And this investigation may (or may not) actually happen, because the IPCC are actually handling it themselves, so we live in hope.
Most people have no idea what happens with police complaints.
In the vast majority of cases, complaints are investigated by the same police force that the public complain about, they have a 'Chinese Wall' in place, i.e. they have a 'Professional Standards Department' that is allegedly both separate from and independent of the rest of the force, but in reality that's just b*****ks and their real job seems to be to find that nothing untoward has ever occurred, with the odd exception that they may find that an overworked front line officer may have made a small and inconsequential paperwork error. The IPCC will do absolutely nothing unless the complaint is about an officer
above the rank of Chief Superintendent. Even if the complaint is sent directly to the IPCC, they will just forward it to the police force... The only exceptions to this rule AFAIK is where the investigation is about a death in custody or a police shooting.
There is an appeal process to the IPCC from the findings of the police's own incestuous investigation, but the terms of reference are limited to investigating whether or not the investigation itself was carried out in accordance with the standard procedure, there is no investigation possible into the conclusions drawn. And it can only be based on the evidence that the individual police force admit to having, not to what they did have or should have had. And, as the public have no way of even knowing what evidence the complaint investigation was based on, it wouldn't even help if the IPCC could investigate the evidence that the police actually had.
And once they've rejected the appeal, there is nowhere else to go.
In other words, if the police act improperly then there is no real investigative process to hold them to account.