A police officer - still on duty - in London has admitted to committing 24 rapes;
In abuses over nearly two decades, making him one of the most numerous sex offenders in Britain.
The Metropolitan Police and the British Public Prosecution Service said that David Carrick, 48, used his position to control his victims, intimidating them and informing them that any complaint against him would not be heard.
The Metropolitan Police, already suffering from a collapse of public confidence in them after a series of scandals, apologized for failing to expose the abuses earlier.
"This man has abused women in the most despicable way," Metropolitan Police Commissioner Mark Rowley said in a statement.
"We failed, I'm sorry, it shouldn't have been a police officer," he added.
A spokesman for British Prime Minister Rishi Sunak described the case as "appalling".
London Mayor Sadiq Khan said there were important questions to be answered after Carrick pleaded guilty to 49 counts brought against 12 victims between 2003 and 2020.
"This is a horrific case," Sunak's spokesman said. "The prime minister expresses his solidarity with all the victims."
"The police force must root out these officers to restore the public's trust that has been shattered by such events," he added.