Police are reviewing a controversial investigation into an interview with historian David Starkey to ensure it is “proportionate”.
It recently emerged that the Metropolitan Police had launched an investigation into a potential public order offence, sparking concern among some politicians including the current home secretary and her predecessor Sajid Javid.
On Wednesday, Scotland Yard said that a review of the probe was being undertaken and that two scheduled interviews had been postponed.
A statement, which did not name Dr Starkey or Mr Grimes, said: “On 4 July, the Metropolitan Police Service was passed an allegation from Durham Police of a public order offence relating to a social media video posted on 30 June.
"The matter was reviewed by officers and on 29 July a file was submitted to the Crown Prosecution Service (CPS) for early investigative advice.
"On 25 September, early investigative advice was received and officers began an investigation. No arrests have been made.
"On Monday 12 October, a senior officer was appointed to conduct a review of the investigation to ensure it remains proportionate and that all appropriate lines of inquiry are being considered.”
Mr Grimes previously called the investigation a waste of money and police time, and claimed it impinges on press freedom.
Dr Starkey defended Mr Grimes, saying it was “unfortunate and grossly unfair” to allegedly focus the investigation on the interviewer.
The 75-year-old said: “Mr Grimes is a young, aspiring journalist and his role in the affair is - at most - secondary.
"I have apologised unreservedly for the words used and I do so again today. It was a serious error for which I have already paid a significant price.
“I did not, however, intend to stir up racial hatred and there was nothing about the circumstances of the broadcast which made it likely to do so.”
Dr Starkey said the Met had sought to contact him by email on the same day it notified Mr Grimes about the investigation, but claimed it was sent to the Bow Group conservative think tank, of which he is vice-president.
As a result, Dr Starkey said he only received the email on Tuesday morning when it was forwarded to him.
“The effect of this delay and confusion has been to throw the focus of the police investigation wholly on Mr Grimes. This is unfortunate and grossly unfair,” he added.
Dr Starkey said he would cooperate with police, but added he will “defend myself robustly against any allegation of criminal wrongdoing”.
The Society of Editors, which aims to protect media freedom, said it was “deeply concerned by the threat such an investigation poses to free speech and the chilling effect it could have on the media's ability to interview controversial figures”.
Additional reporting by PA