People with different opinions from the prevailing liberal ideology are increasingly being scared into silence by "politicized" police forces and the threat of investigations, fines and jail time, warns the head of a Christian advocacy group.

Paul Coleman, executive director of ADF International, writes in European Conservative that what seemed unthinkable in the West just 10 years ago is now coming true after a number of arrests and investigations. 

These include Finnish politican Päivi Räsänen, former policeman Harry Miller, and Catholic journalist Caroline Farrow. 

Earlier this month, Farrow shared pictures on her Twitter of police arresting her for allegedly posting "malicious" material online.

She was released after a few hours under investigation but it is not Farrow's first run-in with the police as she was previously investigated for allegedly misgendering a transgender person. In that particular case, police eventually decided that no further action would be taken. 

Coleman said that Farrow and others were among the few "courageous" citizens speaking up for free speech. 

"What seemed unthinkable just a decade ago is coming true across the West, as politicized police forces use grueling investigations and arrests to scare people into silence. All too often, it works," he said. 

"The time lost; the expense; the fear and the stress on family, friends, career, community; the ever-present specter of massive fines or even jail time; the simple reality that voicing an unpopular opinion could lead to all this has a chilling effect on free speech."

He encouraged people to "stand up against the bullying". 

"No police force should be allowed to threaten or arrest someone because of their beliefs," he said. 

He concluded, "When someone faces criminal charges for voicing their beliefs, everyone—whether they agree or not—should pay attention. The reality is that if the government can threaten and punish Caroline or Päivi for their convictions, they can punish anyone."