Police have "betrayed their commitment to neutrality" through partnerships with LGBT lobby groups like Stonewall, a report by free speech campaigners has said.
'Through the Looking Glass', by Fair Cop, accuses the police of "craven kowtowing" to Stonewall and other LGBT lobby groups instead of serving the wider public.
British police have, the report says, become "lost in a political wonderland" and have "actively adopted a brand of politicised policing" that has led to the criminalisation of people "for expressing lawful opinions online".
It goes on to argue that active participation in events like Pride contradicts the police Code of Ethics, which restricts activity that gives the impression of being political.
"Except in those instances where, as a profession, the police hold particular and unique expertise in a subject - traffic or gun law, the welfare of police dogs, perhaps - the political beliefs of a police officer should remain as mysterious as those of the Queen," the report reads.
"There is a good reason why Her Majesty has never been spotted wearing a Brexit badge or rainbow lanyard."
Fair Cop was founded by Harry Miller, a former officer who was visited by Humberside Police in January 2019 over alleged transphobia after tweeting about the transgender debate.
One of the tweets which prompted the police probe said: "I was assigned mammal at birth, but my orientation is fish. Don't mis-species me."
Miller said the police told him they needed to "check your thinking" and that while no crime had been committed, they would lodge the incident as a non-crime "hate incident".
Mr Miller was exonerated earlier this year when the High Court deemed the force's actions a "disproportionate interference" with his right to freedom of expression.
Welcoming the report from Fair Cop, the Christian Legal Centre's Roger Kiska said that some police equality training gave officers a "wholly inaccurate perception of what is actually legal and what is not".
"Some police, as the report highlights, have been open in their belief that misgendering can be a form of abuse," he said.
"The police have also been very open in their support of Pride events, through actual participation and support through social media.
"One of the hallmarks of a functioning democracy is the separation of powers. In the United Kingdom, government makes the laws, judges resolve it and police enforce it.
"This separation has been compromised by law enforcement's acquiescence to LGBT campaigning aspirations and their increasingly chummy relationship with Stonewall and Pride.
"Its political neutrality on issues of intimate moral concern and genuine public debate has been horribly compromised."