At least 60 campaigners have walked out of the inquiry into undercover policing demanding that its chairman stands down or appoint a full panel for the rest of the hearings.
There has been growing discontent among core participants at the inquiry, which started in 2015 and was due to finish this year, but has been beset by delays.
Phillippa Kaufmann QC, representing the group, told the Royal Courts of Justice on Wednesday:
The campaigners have raised concerns about former undercover officers being granted anonymity during the proceedings, and also the slow speed of progress.
Ms Kaufmann claimed that the chairman's reasoning for not releasing the names of certain police officers was "scant and largely uninformative".
She said her clients "therefore ask that you recuse yourself of this enquiry or that you bring about a new panel.
"I'm instructed with the entire legal team to withdraw while these issues are considered by you. So that is all I have to say this morning."
Her words were greeted by cheers and applause inside the courtroom, followed by the vast majority of the public gallery streaming out.
Campaigners would like to see an inquiry led by a panel rather than a single judge, because they believe that would better investigate claims of institutional racism and sexism.