Writing on his blog, Mr. Linehan said he was taken into police custody, searched and interviewed in relation to three posts he made on X in April, including one that read: “If a trans-identified male is in a female-only space, he is committing a violent, abusive act. Make a scene, call the cops and if all else fails, punch him in the balls.”

Mr. Rowley defended the arrest in his statement, saying that the law “dictates that a threat to punch someone from a protected group could be an offense” and that “most reasonable people would agree that genuine threats of physical violence against an identified person or group should be acted upon by officers.”

In the 12 months that ended in March 2024, almost 4,800 hate crimes were recorded against transgender people, British police data shows, up from 2,800 hate crimes in the 12 months that ended in March 2021.

Mr. Linehan, 57, is set to go on trial on Thursday on separate charges of harassing an 18-year-old campaigner for transgender rights, accusations he denies.