A transsexual police officer is suing Essex Police after she was allegedly forced to repeatedly 'out' herself over the police radio system when being challenged over her identity.

PC Chapman, 44, claims that her employers failed to properly investigate the incidents and did not educate officers about transgender issues.

Essex Police disputes the allegations which are currently being considered by an employment tribunal.

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PC Chapman underwent gender reassignment in 1999 while she was serving as a volunteer with Essex Police. Four years later she became a full-time constable.

According to court documents obtained by the BBC the first incident happened in October 2012 when a radio operator did not believe who she was, saying she had a "male voice".

When challenged over her identity she replied: 'I am a transsexual'.

"I felt very embarrassed and desperate. The incident took my breath away," she said in her witness statement.

PC Chapman described the incident as creating a "combination of alarm and distress" and leaving her "very distressed" that she'd had to "out herself" over the radio channel which was being potentially listened to by hundreds of other officers.

According to the documents PC Chapman alleges that two further incidents took place in June of this year when she was once again challenged by control room staff who doubted her identity.

In her statement to the court she said: "I felt a growing sense of apprehension whenever I had to use the radio, concerned that there may be further, similar incidents."

"The radio is also a lifeline at times and I should not have to feel hesitant or anxious about using it."

According to the BBC PC Chapman decided not to be "open" any longer and 'stepped away' from dealing with transgender issues in 2009.

A decision in the case, which was heard at the East London Tribunal Court last week, is expected in the next few months.