The country's top civil servant, Sir Jeremy Heywood, was criticised by MPs for failing to properly investigate the "plebgate" incident that cost the Chief Whip, Andrew Mitchell, his job.
Mr Jeremy told MPs that Downing Street had considered whether Mr Mitchell was the victim of a conspiracy, but decided not to inform police. He also told MPs he didn't think it was appropriate to ask to check the police log:
"We accepted there were unanswered questions, such as a gigantic conspiracy, or a small conspiracy." Political Editor Tom Bradby reports:
Britain's most senior police officer has promised a "ruthless" investigation into an alleged conspiracy against Andrew Mitchell.
Andrew Mitchell has written a piece in which he has accused the police of trying to destroy his career in a smear campaign.
Police investigating the row involving Andrew Mitchell have arrested a second man today. See how the "plebgate" events unfolded.