Having not tweeted since November, JK Rowling broke her Twitter silence to speak out in support of a researcher who lost an employment tribunal case for using “offensive and exclusionary” language on Twitter.

Rowling tweeted about Maya Forstater, who lost her job at an international thinktank after a series of tweets, including one in which she said: “Men cannot change into women.”

Rowling, who has 14.6 million followers, said in the tweet: “Dress however you please (…) But force women out of their jobs for stating that sex is real?” She referenced the case using the hashtag #IStandWithMaya.

Forstater lost her job as a visiting fellow at the Centre for Global Development, an anti-poverty thinktank that has offices in London and Washington.

She was accused at the employment tribunal of having retweeted transphobic material, including a newspaper cartoon of a person flashing two women at a London swimming pond, with the caption “It’s alright – it’s a woman’s penis”.

Court documents show that she had previously tweeted that “it is unfair and unsafe for trans women to compete in women’s sport”.

She was also accused of gendering a non-binary person, Gregor Murray. Forstater responded: “I had simply forgotten that this man demands to be referred to by the plural pronouns ‘they’ and ‘them’… In reality Murray is a man … Women and children in particular should not be forced to lie or obfuscate about someone’s sex.”

Murray is Scotland’s only openly trans elected representative, and was previously suspended after using abusive language towards anonymous protesters at London Pride, and also calling her a “terf” (trans-exclusionary radical feminist). Murray apologised but said “terf” should not be considered an offensive word.

James Tayler, the ruling judge, concluded that Forstater did not have the right to ignore or deny the legal rights of trans people and said her tweets were “incompatible with human dignity and fundamental rights of others”.

Judge Tayler said Forstater had not acknowledged the “enormous pain that can be caused by misgendering a person”. If she had won the case, Tayler said, it would have set a precedent that would prevent employers from dismissing staff expressing similar views about LGBTQ+ rights.

Forstater tweeted after the ruling to say she was shocked. She wrote: “Judgement received. Bad news (for now) Stonewall law won this round. Here is my statement in thread form. I struggle to express the shock and disbelief I feel at reading this judgment.”

Rowling had previously been criticised for liking a tweet that referred to trans women as “men in dresses”. Rowling’s representative later blamed a “middle-age moment” for the like, and said it stemmed from the author mishandling her phone.