A British policeman accused of falsely claiming to have witnessed a senior politician insult police officers has pleaded guilty to misconduct in a public office.

Keith Wallis' claim that he saw Conservative Party politician Andrew Mitchell swearing — and directing the derogatory term 'pleb' at police — in September 2012 triggered a scandal that raised questions about the integrity of Britain's largest police force.

Mitchell was forced to resign, but denied the accusations. A dispute erupted over whether police were telling the truth.

On Friday, the 53-year-old Wallis admitted lying about witnessing the altercation. He will be sentenced later.

In a statement, Scotland Yard Commissioner Bernard Hogan-Howe apologized to Mitchell. He said Wallis' actions have damaged public trust in police officers.