Tara Mellor had been allowed to use a room at Mirfield Free Grammar School after returning from maternity leave in 2019, but was then told that was “not an option” after her second child was born the following year, due to Covid-19 restrictions.
An employment tribunal heard she submitted several written requests for a room where she could express milk to give to her daughter, but they were refused.
The citizenship teacher said she was “forced” to express in the "dirty" toilets and the car park, after returning to work in September 2020.
She was also forced to take time off work when she began suffering from mastitis – a painful condition which can be caused by a buildup of breast milk.
She told the tribunal in Hull: “I found it unhygienic and disgusting to have to express in the toilets.
“Further, as I wasn’t allocated any time to express, I had to do it at lunch time and eat my lunch at the same time.
“I found it disgusting to have to eat my lunch in toilets, which were often dirty”.
The teacher also told the school she was concerned about “leaking” during lessons and she would be in pain if she was not able to express during the day.
The school, which is run by MFG Academies Trust, said it was not possible to provide the teacher with a private room, as many were “out of use” due to social distancing restrictions - but a panel of three employment judges rejected that argument.
Ms Mellor won the sexual harassment case after the panel ruled the school’s decision to make her use the toilets was “degrading”.
The ruling stated: “The (school) sought to argue that the fact that the claimant did not raise this in the form of a grievance or complaint suggested it was not that bad, or that it was the claimant’s choice. We do not agree.
“The claimant had a very short lunch break of only 25 minutes. The uncontested evidence was that expressing took about 20 minutes.
“We have also referred to the busy nature of the claimant’s working day, and the claimant had raised the issue very many times through her line manager.
“The fact that the claimant chose to express in an unacceptable environment rather than run the risk of leaking in the afternoon or, as far as she believed, develop mastitis does not diminish the impact of the environment in which she was required to express milk and eat her lunch.
“Consequently, in our judgement, the conduct did have the effect of creating a degrading or humiliating environment for the claimant.
“We are aware of the seriousness of these words, but in our view a woman who has recently given birth should not be subjected to these circumstances solely because she has done so.”