Plain-clothes officers 'were deployed at G20 demo'
Scotland Yard has admitted giving MPs inaccurate information by denying "covert officers" were deployed at London's G20 protests in April 2009.
Commander Bob Broadhurst told the Home Affairs Select Committee a month after the protest that no plain clothes officers were deployed in the crowd.
He said it would have been too dangerous to do so.
The Met said the officers were covertly deployed to identify individuals who may be involved in criminal activity.
In a statement, the Metropolitan Police said it had established that covert officers had been deployed to the protests, after officials made thorough checks following recent media reports.
Last week, committee chairman Keith Vaz wrote to the Met's Commissioner Sir Paul Stephenson.
The letter came after questions arose about Mr Broadhurst's evidence following the unmasking of undercover policeman Mark Kennedy, who attended many demonstrations during seven years living as a spy among green activists.
Giving evidence at the select committee in 2009, Commander Bob Broadhurst told MPs then: "The only officers we deploy for intelligence purposes at public order are forward intelligence team officers who are wearing full police uniforms with a yellow jacket with blue shoulders.
"There were no plain clothes officers deployed at all."
However, the Met stood by Sir Paul's assurance to the committee at the same hearing that the force did not use "agents provocateurs" - undercover officers actively encouraging unrest.
The G20 protests were timed to coincide with the world leaders' summit in London in April 2009.
The Met statement released on Wednesday said: "Having made thorough checks on the back of recent media reporting we have now established that covert officers were deployed during the G20 protests.
"Therefore the information that was given by Commander Bob Broadhurst to the Home Affairs Select Committee saying that 'We had no plain-clothes officers deployed within the crowd' was not accurate."
The statement added: "Prior to the evidence session, there had been extensive discussion in the media and then at parliamentary committees about allegations that police officers were acting as agent provocateurs in the protests."
Such behaviour was "completely against" how the Met deploys officers, the statement said.
It said the commissioner's comments at the select committee referred to this point, not to covert deployments.