This reminded me of some slightly-pissed musings I was having last night.
Suppose someone, aware of what happened, were to be transported back in time to that night - to the moment captured on the CCTV when Sarah Everard was "arrested". What would they do? What
could they do. Armed with hindsight, I imagine it wouldn't be quite as hard to walk up and challenge the arrest...but what then? The perpetrator may well get spooked, and do a runner. You might call the police - interesting conversation - and say "I think someone just tried to abduct someone by flashing their warrant card. They've got abduction stuff in the car" (you'd know this, because you read the sentencing report before you travelled back in time).
Does anyone think that there's much likelihood that this would even be followed up? Or that a hue-and-cry might ensue to prevent another woman, somewhere else, being abducted? Given the way the police have been talking since the sentencing, my feeling is that it'd be dismissed, or waved away - there'd be a denial that it could possibly be an active police officer, that the warrant card was real, or that any threat existed.
With policing as it is right now, I'd say that the chances of stopping something like this happening again are just as minimal as they were before Sarah Everard was abducted. It's not even "closing ranks" - I think there is an institutional perception that this kind of thing just doesn't happen. Until it does, and even then they'll busily "other" the offender, and carry on exactly the same. The only thing, I think, that makes this a comparatively rare event is the fact that most people, even coppers, don't get to the stage where abducting and murdering women is an option. But that's no thanks to the police, their processes, or their willingness to take a very hard look at themselves.
We are no further on since this prosecution than we were before it happened, and I see no appetite for change within police institutions.