A Bristol court is this week hearing the legal challenge of four Christian preachers against Avon and Somerset Police.
Mike Overd, Don Karns, Mike Stockwell and AJ Clarke accuse the police of assault, false imprisonment, malicious prosecution, abuse of power and infringing their human rights.
Mr Overd is also challenging the police for what he claims has been an eight-year "sustained campaign of harassment" against him.
Body cam footage from 2016 showed Mr Overd being pulled to the ground and screaming in pain after police showed up to his street preaching outside Bristol's Broadmead Shopping Centre.
He was then handcuffed and held in police custody for over seven hours.
He had been preaching alongside the three other men at the time and drawing a large crowd when police claimed they were "causing a disturbance".
The Christian Legal Centre (CLC), representing the four preachers, said Mr Overd was told by police after his arrest that there was "a line of freedom of speech" and that he was "aggravating people", "challenging homophobia" and "challenging Muslims".
Mr Overd told police: "We were just saying what the Bible says."
All four of the preachers were detained for over six hours following the incident but were eventually acquitted following a trial.
Mr Overd said the police, who have never apologised, "must be held to account for their actions."
"The freedom to preach the message of the gospel on the streets of the UK to the lost, is one of our fundamental rights in this country. If we lose that right, we will begin to lose every other freedom," he said,
"I believe I should be free to express views of public interest, including on culture or morality. I never use profanity, I do not attack people, however I accept that I do criticise ideologies, other religions and certain sexual practises. Ultimately free speech is worthless without the freedom to offend.
"The attitude and approach from the police is that if they receive a report that a Christian is being 'offensive', they turn up arrest first, ask questions later. There has to be a cultural shift in British policing, not just in Somerset, but across the UK."
CLC Chief Executive Andrea Williams said that being offended was "an entirely subjective concept" and "cannot be used as the primary means to decide whether lawful preaching can be stopped and the preachers deprived of their freedom".
Any suggestion that there is a right to not be offended "must be strongly resisted", she added.
"Mr Overd and his friends are motivated by love. They want to share the good news of Jesus with people who might not otherwise hear it. Sometimes that means addressing the false claims of other religions or ideologies," she said.
"Robust debate is often necessary, especially when objections are being raised or abuse is hurled. We shouldn't be afraid of it.
"The aggressive treatment of Mr Overd and his friends by the police and prosecution is shocking. The police should be defending freedom of speech, not clamping down on it."
She added: "We cannot allow the gospel to be shut out of public debate, and that is what is at stake in this crucial case."
