Meet Bob. Bob was exercising his guaranteed right of freedom of expression by shouting to a high profile politician remarks which implied in no soft terms that they are a corrupt tyrant.
Police quickly gather around Bob to begin stalling for time by keeping Bob occupied by questioning him while the VIP politician had time to get away while spared the nuisance of being reminded how much the human race loathes him.
The police seem to be going for an angle of justifying this interference by pretending to be treating it as a potential public order offence which they haven't yet certainly ascertained the commission or non commission of despite undeniably fully understanding that nothing of a sort that would even make it to, much less stand up in court had been done or uttered.
The senior officer having gotten Bob's side of the story then disappears to get other nearby witnesses' versions of events while some more junior officers stay with Bob asking for his details like full name and date of birth which Bob willingly gives them.
The crux of the question is, the senior officer's MO seemed to be to be as unobtrusive as he could justify, that is to say he first wanted to ascertain the facts that were the reason for his potential interest in the various individuals involved before being concerned about their identities. Presumably if it had been determined that no offence had been committed, then he wouldn't have cared about Bob's identity. The more junior officers who were also incidentally from a different collaborating police force on the other hand were in a sense being as opportunistically intrusive as they could manage to. That is to say before the senior officer had even completed his inquiries as to the facts and circumstances that were the very reason for his attendance they were eager to ascertain Bob's identity in case they could find something on the PNC like a circulation etc.
Is there any statutory or non statutory or even binding or non binding code which governs which of these two approaches is actually to be used? And legally, was Bob entitled to refuse to identify himself to the police, or to demand to know the grounds on which they were requiring him to do so?