The Old Vic theatre says it has received 20 personal testimonies of alleged inappropriate behaviour by Kevin Spacey, who was its artistic director between 2004 and 2015.
Those affected said they “felt unable to raise concerns”, and he “operated without sufficient accountability”.
The London theatre said it “truly apologises” for not creating a culture where people felt able to speak freely.
The BBC has contacted Spacey’s legal representatives for comment.
The Old Vic’s announcement follows recent allegations of sexual harassment and predatory behaviour made against the double Oscar winner and former House of Cards actor while at the theatre.
Spacey has not responded to them.