Andrew Mitchell has demanded a full investigation into the "Plebgate" scandal after a Dispatches and Channel 4 News investigation cast doubt on police log book accounts leaked to the media.
The report alleges that a police officer posed as a member of the public and falsely claimed to have witnessed the incident that took place in Downing Street in September.
It claims the version of events a constituent emailed Deputy Chief Whip John Randall matched the police story that later appeared in The Daily Telegraph "almost word for word".
It is understood that the person who wrote to Mr Randall is a serving police officer who later told the programme, "I wasn't a witness to anything".
Channel 4 News also broadcast CCTV footage of the moment Andrew Mitchell had an exchange with Downing Street police officers for the first time.
Mr Mitchell, who resigned as Chief Whip following the row, told the programme that the allegations made against him were "completely untrue", but admitted he had sworn at the officers.
He claimed the email sent to Mr Randall was "false", adding it was "clearly aimed to destabilise me and finish me off by sending it to the heart of government, to my deputy".
The programme said its key findings were:
- The constituent's email sent to Deputy Chief Whip John Randall complaining of Mitchell's behaviour matched the police story leaked to The Daily Telegraph
- The email was sent by a serving police officer
- The man understood to have sent the email later told the programme, "I wasn't witness to anything"
- CCTV footage shows there were no crowds of people watching and listening to the incident, contrary to the log book account
- Police Federation officers said Mitchell refused to tell his side of the story during a meeting, but a recording - which was broadcast by Channel 4 News - shows he did
Number 10 said the allegations that a serving police officer posed as a member of the public and fabricated evidence were "exceptionally serious", adding it is essential the police "get to the bottom of this as a matter of urgency".
Mayor of London Boris Johnson agreed, saying these "very serious allegations" must be investigated "with all possible urgency".