When Caroline Farrow, a Catholic commentator, and transgender rights campaigner Susie Green, agreed to take part in a television debate about a controversial Girl Guides policy, producers would have expected differences of opinion.
But while the conversation on screen was certainly heated, it was what happened off-air when the pair continued the debate on Twitter that resulted in a six-month-long police investigation.
Mrs Farrow, a mother of five with strong religious views, allegedly used the wrong pronoun when referring to Ms Green's transgender daughter.
Ms Green was so angered by what she described as a "distressing and spiteful" attack that she lodged a formal complaint with Surrey police.
On Monday night, they contacted Mrs Farrow and asked her to attend a voluntary police interview.
The response by a police force which, like all others, is struggling to cope with violent crime and knife violence, will raise eyebrows and further fuel the debate around police priorities.
In November Sara Thornton, head of the National Police Chief's Council, warned that the increasing focus on investigating hate crime was putting a strain on resources at a time when forces were struggling to deal with rising levels of violence.
Her comments were echoed by the Met Commissioner, Cressida Dick, who also said police officers ought to prioritise the issues that people cared about most, such as violence and knife crime.
But campaigners who support transgender rights insist it is the police's place to bear down on those alleged to flout the Equalities Act and seek to cause harm and distress to vulnerable people.
Dr Jane Hamlin, president of the Beaumont Society, a charity which supports trans people, said that mis-gendering is "very hurtful".
"People sometimes do it by accident, even my friends accidentally get it wrong but they always apologise immediately afterwards.
"But to do it publicly like that, it's dreadfully thoughtless and certainly something that should not be done."
Asked whether police should investigate such issues, Dr Hamlin added: "It seems reasonable to me because it contravenes the Equalities Act. It depends whether that's the case [in this case] and I would recommend that people do report in situations like that - especially when it's so public, it's not a slip of the tongue, it can be a deliberate action."
The television debate, with Piers Morgan and Susanna Reid, took place on Sept 26 following a decision by the Girl Guides to dismiss two leaders who refused to apply its policy not to inform parents when a transgender child joins.
Ms Green passionately defended the policy, arguing that telling people that a transgender member had joined could lead to the youngster being singled out or "othered", leading in turn to possible bullying and abuse.
She told viewers: "The reason they are identifying as female is because they don't identify with their body, so they are far more likely to have issues around that. There is no evidence whatsoever to say that trans girls are a threat and any issue around abuse has never happened.
This policy is a couple of years old, has been around a long time and it seems like every time there's an opportunity to have a go at trans girls [people take it]; these are children who want to be with their friends."
Mrs Farrow replied she would be unhappy to let her daughter join the Guides as she believed the policy risked girls' safety.
She said transgender girls should be kept separated from other girls for the same reasons boys and girls were kept apart in other matters.
The spat continued on social media and three weeks later the police assigned to an officer to establish whether there had been a breach of the Malicious Communications Act.
Had a message from Guildford police tonight about my tweets following an appearance on @GMB with Susie Green and Piers Morgan. Susie Green has reported me for misgendering her daughter.— Caroline Farrow (@CF_Farrow) March 18, 2019
This involves material that is grossly offensive or threatening or is false or believed to be false and that is sent with the intention of causing distress or anxiety. Officers contacted Mrs Farrow again on Monday, despite Ms Green indicating that she no longer wished it to be a police matter.
Perhaps understandably, Mrs Farrow described her outrage on Twitter at the development, posting: "I have pointed out to the police that I am a Catholic journalist/commentator and it is my religious belief that a person cannot change sex [and] that we are in the middle of a national conversation about what it means to be male and what it means to be female.
"Nonetheless, following my appearance on national television, the CPS [has] decided I need to be interviewed under caution for misgendering Susie Green's child."
She went on: "I don't even remember said tweets. This was in September. I have done nothing wrong, nothing illegal and will happily do jail time for my right to say that people cannot change sex."
I don’t even remember said tweets. This was in September! But I really not got give a flying toss. I have done nothing wrong, nothing illegal and will happily do jail time for my right to say that people cannot change sex.— Caroline Farrow (@CF_Farrow) March 18, 2019
Mrs Farrow also pointed out that since the row had blown up on Twitter she and her family had been subjected to abuse and threats by internet trolls.
She said one had even published photographs that identified her children as well as bombarding her with sexually humiliating insults.
Last night a police spokesman confirmed that officers were looking into those complaints.
Ms Green heads up Mermaids, Britain's leading transgender charity, which helps support youngsters and their families who are dealing with such issues. The charity provides advice to government agencies, NHS staff, the police, social workers, the Scouts and nursing students.
Ms Green's daughter, Jackie, 25, became the youngest person in Britain to transition when she changed her sex from male to female almost 10 years ago.
Since then, Jackie has reached the semi-finals of Miss England and models around the world, describing herself as "just a normal girl with a bit of an interesting history".
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