Persons rights inside government owned buildings ?

[waterworks]

A certain set of loud mouthed people online beleive as a taxpayer ( they probably don't pay any ) they cannot be asked to leave public accessible government buildings such as libraries, jobcentres, police station foyers and council offices when asked to do so ?

I would say the staff are authorised by the land owner to ask anyone to leave for any reason and then it becomes a trespass?

what does the law say about this ?

[PallasAthena]

Is this referring to the provocateurs on the "Auditing Britain" YouTube channel?