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:
Sir Jeremy Heywood, the Cabinet Secretary, was criticised by MPs after admitting he didn't probe the word 'pleb' in his investigation of the events that led to the resignation of former Tory Chief Whip Andrew Mitchell.
ITV News Correspondent Juliet Bremner reports:
Cabinet Secretary Sir Jeremy Heywood has insisted that he did a "competent" job during his investigation into the 'Plebgate' incident involving former Chief Whip Andrew Mitchell and police officers at Downing Street.
He said he told Mr Cameron that CCTV footage showed "inaccuracies and inconsistencies" in emails sent by someone who claimed to have seen the altercation last September.
Sir Jeremy said this meant they should not be relied upon in deciding whether Mr Mitchell should be sacked.
When challenged by members of the Public Administration Select Committee, about his suitability to carry out an inquiry into the incident, he said:
"It's a perfectly legitimate part of my role and frankly, I think I did the job competently and came to the right conclusion."
The Cabinet Secretary Sir Jeremy Heywood has said that after Andrew Mitchell resigned he came back in November and asked to see the CCTV footage of his row with a Downing Street police officer.
When Mr Mitchell viewed the footage, he then asked for a copy to take away.
Conservative MP, Charlie Elphicke, then asked Sir Jeremy why he did not share the CCTV footage with Mr Mitchell before he resigned given that he had previously concluded there were discrepancies between it and the police log.
Sir Jeremy said:
I'm pretty sure that he was told the broad conclusions of my report and he didn't at that point ask to see the CCTV footage. If he had asked to see it, we would have let him see it.
On Tuesday 25 September, the Cabinet Secretary Jeremy Heywood became aware of a discrepancy between the CCTV footage of the incident involving and the police log.
He was asked by the Public Administration Select Committee, if he had shared his concerns with the police at the time.
He said: "No, my report was to the Prime Minister not to the police".
– Cabinet Secretary Sir Jeremy Heywood
I looked at it very carefully, I didn't rush to a judgement, I looked at it several times and at different cameras. I would say it was inconclusive and unreliable.
The Cabinet Secretary Jeremy Heywood is giving evidence to Public Administration Select Committee about the resignation of former Chief Whip Andrew Mitchell.
Sir Jeremy was asked by the Prime Minister to investigate the claims against Mr Mitchell about the incident involving a police officer at the Downing Street gates when they were first reported last September.
Sir Jeremy has told the committee he did three things.
Firstly, he spoke to Mr Mitchell about the incident in person, secondly, he examined CCTV footage at Number 10 and the Foreign Office.
He also said he sought to meet the person who had sent an email about it to the Conservative MP John Randall - who was Mr Mitchell's deputy at the time - but they did not want to meet him.
Sir Jeremy later reported back to Mr Cameron that it was impossible to ascertain exactly what had happened and the Prime Minister decided to support his embattled Chief Whip.
Met Police Commissioner Sir Bernard Hogan-Howe told MPs at the Home Affairs Select Committee that the police officer arrested as part of the ongoing investigation into the "plebgate" row would answer bail on January 31, whilst his relative would answer bail on January 16.
He said a case would be handed to the Crown Prosecution Service (CPS) by the end of the month, and that the inquiry set out to investigate the "circumstances surrounding the police officer's claims to witnessing the incident on Downing Street" and establish if there was evidence of "conspiracy".
– Met Police Commissioner Sir Bernard Hogan-Howe
We expect we may be able to share a report with the CPS by the end of this month. A matter of weeks before we do as much as we can."
The head of the Metropolitan Police said he had an "open minded' approach to the ongoing "plebgate" investigation, as he appeared in front of MPs at the Home Affairs Select Committee earlier today.
Met Commissioner Sir Bernard Hogan-Howe apologised to MPs for his earlier assertion that he would "stand by" his officers 100%, shortly after the allegations originally emerged. He said:
"I do have an open mind. If any comment that I have made left anyone thinking I couldn't have an open mind, I'm sorry....I'm open minded. I will pursue the evidence."
Sir Bernard added that part of the investigation was to identify the source of the leaked police log, which recounted the altercation with Mr Mitchell.
He said if the allegations against the police officers involved were true, "it would be a very serious matter...I don't expect police officers to lie."
Former chief whip Andrew Mitchell does not come out of the "plebgate" affair "smelling of roses", a Conservative Party vice-chairman said today.
Lichfield MP Michael Fabricant took to social media website Twitter to ask a series of questions about the altercation between Mr Mitchell and police officers at the gates of Downing Street, following the release of CCTV footage of the encounter.
Mr Fabricant said: "Witch-hunts are unfair. The witch-hunt against Mitchell was wrong if story was embellished. But the witch-hunt now against the police not good.
"I suspect the truth is 6 of one and half a dozen of the other. NO-ONE comes out of it smelling of roses: neither the police nor Andrew."