Prosecutors are expected to complete an initial review of the Andrew Mitchell "plebgate" evidence within a fortnight, it has been revealed.
The Independent Police Complaints Commission (IPCC) said police had gathered hundreds of statements amid claims of a conspiracy by officers to unseat the former Cabinet minister. However, further forensic and technical work needs to be completed.
IPCC chairwoman Deborah Glass also knocked back Mr Mitchell's calls for an immediate inquiry into apparent media leaks from the investigation, which is being led by Scotland Yard.
In a letter to the Tory MP, Ms Glass wrote: "The Metropolitan Police Service (MPS) has specifically asked the Crown Prosecution Service (CPS) for advice and guidance surrounding the future course of the investigation, in relation to potential criminal charges."
She added: "I will be meeting with the CPS reviewing lawyer when they have completed their initial review, I hope within the next two weeks, to consider this further. The CPS will make the final decision in relation to whether there is sufficient evidence and in the public interest to charge anyone.
"I also understand that the continued passage of time before this situation is resolved, during which speculation will inevitably persist, is extremely frustrating for you. I can only assure you that I am doing all I can to bring this to a fair conclusion - and that the relevant evidence will be published as soon as it possibly can be."
Former chief whip Mr Mitchell strongly denies branding officers "plebs" when they stopped him cycling out of the main Downing Street gates last September, but has admitted swearing. He was eventually forced to resign over the controversy, but doubt has since been cast on some accounts of his behaviour.
In a letter to the IPPC earlier this week Mr Mitchell wrote: "We are deeply dismayed that the Metropolitan Police appear to have leaked part of the report prepared for the Crown Prosecution Service to certain members of the press and spun it to the advantage of the police officers concerned."
But Ms Glass responded: "The press reports in the Times and the Guardian last Friday, which I assume are the ones you are concerned about, refer to the MPS investigation finding 'no evidence that police officers lied'. The articles refer to a file being passed to the CPS but do not actually quote from it. While this does not rule out the possibility of the MPS file having been leaked, it also raises other possibilities, either that someone who may have been connected to the investigation or in possession of material had a conversation with a reporter, or that the author/s of the articles were reporting speculatively."
A CPS spokeswoman said: "No timescale has been set on making a decision or reviewing the evidence, but, as is quite normal in a case like this, we will be keeping in regular contact with both the MPS and IPCC, including any meeting referred to by the IPCC. We are yet to receive a full file of evidence and are therefore unable to speculate as to when any final charging decision might be made."