An internationally renowned researcher on tax avoidance is believed to be the first person in Britain to lose her job for saying that transgender women are not women.

Maya Forstater, 45, was told by her managers that she had used “offensive and exclusionary” language.

She was accused of “fear-mongering” for tweeting her concerns about government proposals to allow people to legally self-identify as the opposite sex.

Forstater has begun employment tribunal proceedings against her former employer, the London office of the Centre for Global Development (CGD) think tank. She hopes it will be a test case establishing that “gender-critical” views — which hold that being a woman is a biological fact, not a feeling — are protected beliefs under equality law. She is starting an