Four female campaigners have been awarded damages in a groundbreaking case in an Israeli court, after their local municipality refused to remove illegal and threatening signs demanding women wear “modest” clothing in public.

The case marks the first time that campaigners against gender segregation in Israel’s ultra-orthodox Jewish communities have persuaded a court to rule against the so-called “modesty signs” – despite the fact that they were deemed unlawful by the attorney general two years ago.

Judge David Gidoni found that the failure of the local authority in the city of Beit Shemesh to take down the signs violated the women’s civil rights. He ruled that the “hurtful, degrading and discriminatory” signs put up by ultra-orthodox radicals “delivered a mortal blow to the rights of women in the city” and instructed Beit Shemesh to compensate the women for their “mental anguish”. The municipality must now pay each of the women 15,000 shekels (£2,530) in compensation.

The signs include “warnings” excluding women from certain buildings and pavements in the city of 80,000, which is about 20 miles south-west of Jerusalem. Another billboard, signed “residents of the neighbourhood”, declares: “Dire warning: It is forbidden to walk on our streets in immodest dress, including slutty clothing worn in a religious style.” Another sign – posted near a synagogue – instructs women to walk on the opposite pavement.

The four women behind the campaign to have the signs removed had all suffered intimidation or been spat on by a minority of the city’s ultra-orthodox male inhabitants.

The municipality in Beit Shemesh – where an ultra-orthodox mayor was elected last year by a slim margin – accepted the signs had been put up without permission and were discriminatory, but its leaders said they feared their removal might prompt violence. The court was told the signs had been removed “several times” but it was claimed they were put up again within minutes.

In recent years Beit Shemesh – a city whose population is 45% ultra-orthodox – has been at the frontline of tension between some ultra-orthodox and secular and non-ultra-orthodox residents, not least over the issue of gender segregation and “modesty”.

Last year an ultra-orthodox man assaulted a religious woman in Beit Shemesh because he thought her skirt was too short. In another controversial incident, in 2011, an eight-year-old girl on her way to school was spat on by ultra-orthodox men because of her perceived immodest dress.

The issue has not been confined to Beit Shemesh. “Modesty signs” are on walls in ultra-orthodox neighbourhoods of Jerusalem, requiring loose clothing and specifying the length of sleeves and height of neckline. The health ministry ordered the removal of similar signs from health clinics in the city of Bnei Brak last year.

This year a series of bus ads in Jerusalem, paid for by an ultra-orthodox modesty campaign, attracted controversy for claiming “short clothing = shortened life”.

One of the plaintiffs in the Beit Shemesh case was Miriam Zussman, who explained to the Guardian why she had decided to go to court. “Personally I had incidents where I was spat on and called insulting names, which is quite shocking. I was also dressed extremely modestly with covered hair, skirts below knee and arms covered.

“My daughter too had an incident near school where she was waiting at bus stop near a boy’s yeshiva [religious school] and was told she wasn’t allowed to wait at the bus stop. It was a growing issue that became tied to the power of ownership the signs represented. The idea came to us that we could do something, especially given the signs are illegal. It is a minority that has been violent but there is a lack of people who are prepared to speak out.”

Nili Philipp, another of the women who brought the case, told Haaretz after the court victory: “We can’t count on our city government to enforce the law in Beit Shemesh. I’m glad we have the courts to stand up for our rights, but as I see it, it’s a sad state of affairs that we had to go to court at all.”

Orly Erez-Likhovski, the chief lawyer at the Israel Religious Action Centre, which represented the women and has been fighting against gender segregation on religious grounds, said the next step was to insist the police remove the signs. “What the municipality said to the court was that if they took them down they would be hung again and there would be violence and riots. Our argument in court on Sunday was that they contribute to the atmosphere of violence against women.

“We have to go back to court to enforce their removal but this is very important first step. It is the first case on modesty signs since the attorney general ruled they were illegal.”