The prosecution was not of the head of the force as an individual but of the office of the head of the force (effectively equivalent to the force itself being p

The prosecution was not of the head of the force as an individual but of the office of the head of the force (effectively equivalent to the force itself being prosecuted - a legal quirk due to the way the force is legally constituted). And it was for breaching the Health and Safety at Work Act, and resulted in a tiny (comparatively speaking) fine. This was viewed by many as a whitewash. More broadly, the whole episode made them look incredibly incompetent, callous and uncaring. No action was taken against the officers who were clearly culpable through their abject incompetence (for example, if he was a potential suicide bomber, why wasn't he stopped before he got on a train?). Furthermore, the force took far too long to apologise and admit errors publicly. And they never adequately explained the tactics that led to an innocent man being shot without warning. This is very similar in character to the issues which plague policing in the USA and has served to sow a great deal of distrust of the police here. Witness the "London riots" in 2011, for example. And that's also set against a background where they have been publicly found to be "institutionally racist". Subsequently to the de Menezes incident, armed police also "accidentally" shot an unarmed suspect in the shoulder while running upstairs in a house in the Forest Gate raid (which again, just makes them look like amateurs). And so on. So our police are very far from perfect - it's just that being better than some of the worst excesses seen in the liberal world is not a hard standard to meet.