POLICE chiefs are threatening to stop four officers from being questioned by a powerful Holyrood committee as the fall-out over a data-beach controversy which has embroiled the national force continues.

Senior officers are seeking legal advice after the Scottish Parliament's justice committee summoned the officers to answer questions about how they investigated the leak of confidential details of a murder inquiry to a newspaper.

The potentially damaging dispute between Police Scotland and MSPs threatens to cause a constitutional row over whether politicians have the right to question serving officers about operational matters.

MSPs believe the officers can cast light on how Police Scotland's Counter-Corruption Unit came to breach new data guidelines designed to protect journalistic sources.

But senior figures in Police Scotland, which is currently without a chief constable, believe that such questioning would amount to unprecedented political interference in operational policing.

Chief Superintendent Andrew Morris said: "We can confirm that four officers have been invited to attend the Justice Committee on January 12. We are currently considering the invitation."

Insiders stressed that Mr Morris's wording is highly unusual.

The force in the past has always immediately agreed to send officers to Holyrood to be questioned by politicians, but these have been chief officers with public accountability roles rather than serving operational ones.

Deputy Chief Constable Neil Richardson, who is currently in charge following Sir Stephen House's departure, said in a letter to the committee seen by The Herald that he is seeking legal advice on whether his officers have to attend.

HeraldScotland: DCC Neil Richardson. Photo: Andrew Cowan/Scottish Parliament

Mr Richardson himself appeared before the committee on Tuesday.

He told MSPs that the breaches had been a "mistake" he blamed on one officer's "misinterpretation" of new guidelines, the speed of their introduction and insufficient training.

However, Independent MSP John Finnie said Mr Richardson had "failed in his responsibility" for ensuring officers complied with the changes.

He defended the summons, saying he would not seek to ask about live investigations or any potential disciplinary proceedings.

Mr Finnie said: "This is a matter of public interest. Any citizen, including police officers, has the right to know that his or her privacy is being respected.

"We have to see the whole picture about these data breaches and understand the chronology."

Asked whether it was appropriate for operational officers to speak before MSPs, he added: "Nobody should be allowed to hide behind titles."

HeraldScotland:

Mr Richardson, as the most senior of the Chief Constable's deputies, was in charge of disciplinary matters.

On Wednesday, he told a meeting of his main civilian watchdog, the Scottish Police Authority, that there had been five breaches of journalistic source rules and that these all referred to a single inquiry.

This inquiry was in to the leaking of confidential information, a criminal offence, in to the investigation of the 2005 murder of a Glasgow prostitute Emma Caldwell.

A newspaper named and pictured a man it said was a suspect in the case. In response, the Counter Corruption Unit looked at the communications data of serving officers, including two phone bills, in an effort to discover who had spoken to an intermediary passing the information on to the newspaper.

Since March, police have had to seek judicial approval to identify journalistic sources.

Last month, Sir Stanley Burton, the Interception of Communications Commissioner, said Police Scotland had contravened the relevant Code of Practice on five occasions.

The body that represents three of the four officers is deeply concerned that its members being named in parliament.

Niven Rennie, president of the Association of Scottish Police Superintendents, described the committee questioning as following "an agenda being set by our national press".

He added: "Some of the questioning was more robust than usual.

"That in itself is not a concern.

"What is a concern to our association was the release of the names of individuals who work in a particularly sensitive area of policing into this public domain."

Mr Rennie has written to Holyrood's presiding office to question the process. In a blog on his association's website, the officer added: "We are not alone in holding such views."

The committee has the power to compel the officers to attend. It has not done so as yet.