An estimated 15,000 in London showed solidarity with and demanded the release of those whom Hamas is holding hostage in Gaza.

Several days after London police shut down the Campaign Against Antisemitism’s billboards showing images of kidnapped children held in Gaza, 15,000 people gathered in Trafalgar Square “to stand in solidarity and to call for the release of the hostages taken by Hamas terrorists,” per the Board of Deputies of British Jews.

Pictures that the nearly 265-year-old representative body shared on social media showed seas of Israeli flags and people holding signs bearing photos of people whom Hamas kidnapped—imagery that resembles the displays that the police had canceled days before.

The solidarity rally was called “Bring Them Home.”

“To give you some idea of what we’re talking about here, this is more than 5% of the entire Jewish population of the UK, assembled at less than 48 hours notice, even taking into account allies in the crowd,” wrote Daniel Sugarman, public affairs director for the Board of Deputies. “The largest gathering of the British Jewish community in decades.”

“We are here today to speak on behalf of those who have been taken from us and have no voice,” said Marie van der Zyl, president of the Board of Deputies, at the event. “We stand here united, with one voice, to say, bring them home.”

In an Oct. 12 press conference in London, family members had shared their anguish having not heard from loved ones, whom Hamas was holding hostage. “People who survived the Holocaust found themselves facing another one,” Noam Sagi, a British-Israeli psychotherapist whose mother was taken hostage, told reporters. He urged reporters to “call Hamas for what they are.”

Sharon Shochat, the British-Israeli director of Defend Israeli Democracy UK and organizer of the press conference, said it was the “biggest hostage crisis the world has faced” in recent years.