A Christian street preacher was arrested in Perth on Wednesday for "breach of the peace".
The Reverend Josh Williamson, pastor of Craigie Reformed Baptist Church, is the third Christian street preacher to be arrested in the UK since July.
The Christian Legal Centre, which reported his arrest, said the trend pointed to "an increasing hostility towards Christianity".
Mr Williamson, who regularly takes to the streets to hand out Christian flyers and engage in open air preaching, was arrested whilst addressing a crowd on one of the main streets in Perth.
The arresting police officer told him he was breaking the law by being in "breach of the peace".
When asked to explain further, the officer contended that the MP3 recorder Mr Williamson was using was too loud.
When Mr Williamson said he was not using any amplification and asked what an acceptable level of volume would be, the officer said the noise level was not the issue but that a complaint had been made against him, the Christian Legal Centre reports.
The officer then told Mr Williamson he would be arrested if he continued to preach. Mr Williamson was arrested when he informed the officer that he would not comply because he was not breaking the law.
A second man, who spoke up in defence of Mr Williamson's right to preach was also arrested at the scene.
Mr Williamson was then taken to Perth police station where he was interviewed before being released with a caution.
The incident follows the arrests of Tony Miano in Wimbledon and Robbie Hughes in Basildon earlier in the summer after complaints were made about their street preaching by members of the public. Both were taken in by police for questioning before being released without charge.
Andrea Minichiello Williams, chief executive of Christian Legal Centre, said: "This is the third arrest in as many months. These street preachers are not breaking any laws and are perfectly within their rights. The police are overreaching their authority and misapplying the law. Their actions show an increasing hostility towards Christianity.
"Freedom of speech is a precious freedom that we must uphold. This injustice must be tackled to halt the chilling effect already felt by many Christians. The threat to freedom of speech is a concern for wider society, not just for Christians.
"It's evident that police all over the UK need clear guidance on this matter. Three wrong arrests in three months just shows the level of ignorance that currently exists. It's up to police chiefs to take a lead and issue guidelines so that this stops happening."