The measure, already used by some police forces, follows guidance from the College of Policing and was only discovered by accident, The Guardian reports.

Now the policing inspectorate is calling on the Metropolitan Police, the UK’s largest force, to introduce the rule. 

The Society of Editors and specialist journalists in the Crime Reporters’ Association, however, are opposed to the move.

Among their concerns are that the order may deter prospective whistleblowers or those who do not trust their bosses to address complaints of wrongdoing.

Ruth Smeeth, chief executive of Index on Censorship, said: “Index is increasingly concerned at the seemingly growing perception within the British police that journalists are seen as unsavoury or potentially disreputable individuals for officers to associate with.

“Freedom of the media is a bedrock of our democracy and the tendency to see reporters as a threat rather than an asset is something we are more used to seeing with our work in authoritarian regimes around the world rather than advanced democracies.”

A spokesperson for the College of Policing said: “Journalists have an important role in holding police to account and supporting the service with news stories including appeals for information. There is a public expectation for the police to have policies in place to protect sensitive information held by the police, which can include details of members of the public and police operations. This includes a requirement to declare any potential conflicts of interest in order to be open and transparent, as well as mitigate any risks that may arise.

“The guidance … should not impede healthy relationships between police and media. We are working with the National Police Chiefs’ Council and others to review the guidance and will listen very carefully to any issues raised by the media.”

A spokesperson for Her Majesty’s Inspectorate of Constabulary and Fire and Rescue Services commented: “We acknowledge the essential role journalists play in our democracy, including holding police forces to account. We make recommendations for police forces, taking into account relevant authorised professional practice where appropriate.”

The Society of Editors said: “The inclusion of journalists within a ‘notifiable associations’ list in counter-corruption guidance gives the wrongful impression that reporters seek to corrupt or deceive and equates the profession with the wrongdoing and dishonesty that journalists work to uncover. A successful working relationship between the police service and journalists is vital to policing legitimacy in the UK.”