I'm being stupid, as this will get downvoted further, because it delves into the justice system deeper than the very top surface, and everyone seems to really like to pretend there is no depth to it at all. In reality, libraries bigger than the average school are filled with books exclusively about the depth of the legal system, so to say that the rabbit hole goes deep is quite the understatement.

1) For example, read https://www.civilservant.org.uk/ethics-no_minister.html (skip to the section on liability, if you must, but ideally don't)

For a more practical story, read, for example:
https://www.noblesolicitors.co.uk/about/indepth-misfeasance....

That points out government workers, in particular police officers, can be held personally and even criminally liable for illegal actions, while at work. Illegal actions, of course, mostly constitute mistakes. But, this is law ... "not knowing the law is no excuse". Whereas not reading the employee handbook can get you fired, but it can never result in liability, never mind criminal persecution. If, in the private sector, your boss orders you to do something illegally, for example drive away with a car the company doesn't own, you are not liable, even if you knew that it was a crime.

In the private sector, it is up to the public prosecutor to prove you maliciously committed a crime while at work. For instance, if you stole a car, a prosecutor will have to prove that you personally benefitted and not just your employer to get a conviction.

By contrast, there is no such requirement for police misfeasance. If a police officer impounds your car for what turns out NOT to be a crime, he cannot avoid personal liability by, even correctly, claim he did not know X is legal.

The police force, or the ministry of Justice is NOT liable, by contrast, unless the public servant involved can prove he was given malicious instructions. In other words: in order to make the police force liable the individual officer has to prove he was given illegal orders at least.

See the turnaround? In the private sector companies are liable "by default". In the public sector "public servants", individuals, are liable "by default". The burden to prove it was someone else's fault shifts.

It's not just police officers, some very famous cases involve doctors being held personally liable for mistakes that are clearly the consequence of an understaffed emergency department. It was NOT the fault of the hospital, or the NHS, that wasn't even seriously discussed.

2) Google "Hierarchy of law". Law is not the exclusive domain of parliament (or rather: in many, many cases parliament has left implementation to government organisations that internally decide many aspects of law)

Specifically, Secondary (or "delegated") legislation in England includes:

Statutory instruments and ministerial orders
By-laws of metropolitan boroughs, county councils, and town councils

https://www.lexisnexis.co.uk/legal/guidance/secondary-or-del...

City hall is one example that definitely has (limited, but even parliament is limited) power to create laws. What many people don't realise: so does the BBC, the NHS, ATC, airports and the phone company.

Generally, most government organisations have their own statutes that are special in the sense that they don't affect just their own organisation (like anything in the private sector), but everyone in society. They are law, and you can be convicted in a court of law for violating them. So yes, most government organisations write their own laws.

3) While technically true, how do you think it works in practice? The Judiciary is, more or less, "middle management" of the police force. Perhaps a bit higher than a line manager, but for example a public prosecutor gives orders to police officers, in any specific case (they decide which actions are taken when a theft is investigated, as opposed to where a traffic cop goes), and they get orders from judges in various capacities (e.g. investigatory judge). They work in the same offices, in the same building. Recently on a documentary there was a case of a police officer being 100% assigned to a particular prosecutor, not to do police work, but as a clerk of sorts for fraud cases.

There is not "the potential for pressure" here. The people that tell police officers what to do have a right of sorts called "prosecutorial discretion": they can, legally, forgive crimes of someone else (subject to some limits, but the only significant limits are geographical and that it doesn't include first degree murder).

When right above you in the management chain management there is someone that has the power to make specific instances of crime legal. What exactly do you think the "workers" will be demanding?