The Commons home affairs committee has decided to summon the Metropolitan police to explain its actions, after its bid – and subsequent climbdown – to make Guardian reporters disclose their sources for articles relating to the phone hacking of the murder victim Milly Dowler.

The deputy assistant commissioner, Mark Simmons, will be called before the committee to answer questions this Friday – the same day his officers had intended to take the Guardian to court.

The briefing will be held in private, it has emerged, although the committee may issue a statement later.

The powerful committee of MPs has already investigated phone hacking and lambasted the Met for its failings.

Keith Vaz MP, chair of the home affairs committee said: "I have asked the Metropolitan police to give the committee a full explanation of why they took this action and to provide us with a timeline as to exactly who was consulted.

"It is essential that we get the full facts."

It came after Simmons, who is head of professionalism issues at Scotland Yard, admitted that invoking the Official Secrets Act in attempts to make the Guardian reveal its confidential sources for stories relating to the phone-hacking scandal was "not appropriate".

He defended the police's duty to investigate "robustly" leaks of information to the media.

But he said claims that Amelia Hill, one of the reporters who broke the scandal, could have incited a source to break the Official Secrets Act – and broken the act herself – should not have formed a part of Scotland Yard's strategy.

The Met had been due to apply on Friday for a production order to obtain all the material the Guardian holds that would help identify sources for the phone-hacking stories.

"The view I came to when I looked at the matter was that the Official Secrets Act was not an appropriate element of the application," Simmons told the BBC.

"We have acknowledged, and I have acknowledged, the role the Guardian has played in the history of what brought us to where we are now both in terms of its focus on phone hacking itself and indeed its focus on the Met's response to that.

"But in all the glare that's been thrown on to our relationships with the media, we have had to ask ourselves the question about how do we do more to ensure that public confidence in our officers treating information that is brought to them in confidence … is maintained."

Simmons said that, although he had been aware that an application was under way, he had not been aware of its detailed content or of the reference to the Official Secrets Act.

After an intervention by the Crown Prosecution Service (CPS), Scotland Yard abandoned its bid to force the Guardian to disclose its sources on Tuesday night.

Simmons said: "What I have clearly done is taken a view, based on consultation with the DPP [director of public prosecutions], based on, as I say, our own legal advice, that the use of the Official Secrets Act this time … was not appropriate, and that's the basis for withdrawing the application."

The statement put out by the Met announcing its retreat left open the possibility that the production order could be applied for again, but the Guardian's lawyers have been told that the police have dropped the application. A senior Yard source said: "It's off the agenda."

The Guardian editor, Alan Rusbridger, cautioned against moves to curb responsible journalism.

"I just hope that in our effort to clean up some of the worst practices we don't completely overreact and try to clamp down on perfectly normal and applaudable reporting," he told BBC Radio 4's Today programme.

"This was a regrettable incident, but let's hope it's over."

The police application was formally made under the Police and Criminal Evidence Act, but with an assertion that Hill had committed an offence under the Official Secrets Act by inciting an officer from Operation Weeting – the Met's investigation into phone hacking – to reveal information.

The Yard source said: "There will be some hard reflection. This was a decision made in good faith, but with no appreciation for the wider consequences. Obviously, the last thing we want to do is to get into a big fight with the media. We do not want to interfere with journalists. In hindsight, the view is that certain things that should have been done were not done, and that is regrettable."

Many lawyers had expressed astonishment at the police resorting to the Official Secrets Act. Their surprise was reinforced on Monday when the director of public prosecutions, Keir Starmer QC, revealed that the CPS had not been contacted by officers before the application was made.

Neil O'May, the Guardian's solicitor, said: "This was always a misconceived application for source material. Journalists' sources are protected in law. For the Metropolitan police to turn on the very newspaper which exposed the failings of the previous police inquiries and reported on hacking by the News of the World was always doomed to failure. The Metropolitan police need to control the officers who are involved in these sensitive areas."

In a statement, the CPS said: "[On] Monday the Metropolitan police asked the CPS for advice in relation to seeking a production order against Guardian Newspapers.

"The CPS has asked that more information be provided to its lawyers and has said that more time will be needed fully to consider the matter. As a result, the scheduled court hearing will not go ahead on Friday. [The Metropolitan police] will consider what application, if any, it will make in due course, once it has received advice from the CPS."

The Met said in a statement: "The Metropolitan police's directorate of professional standards consulted the Crown Prosecution Service about the alleged leaking of information by a police officer from Operation Weeting.

"The CPS has today asked that more information be provided to its lawyers and for appropriate time to consider the matter. In addition the MPS [Metropolitan police service] has taken further legal advice this afternoon and as a result has decided not to pursue, at this time, the application for production orders scheduled for hearing on Friday 23 September. We have agreed with the CPS that we will work jointly with them in considering the next steps.

"This decision does not mean that the investigation has been concluded. This investigation, led by the DPS [directorate of professional standards], not Operation Weeting, has always been about establishing whether a police officer has leaked information, and gathering any evidence that proves or disproves that. Despite recent media reports, there was no intention to target journalists or disregard journalists' obligations to protect their sources."

The picture painted by Met insiders is that a relatively junior officer took the decision to take on the Guardian without consulting his superiors, setting off a calamitous chain of events that saw the Met condemned for an attempted assault on press freedom.

The senior source said: "There were not a lot of happy people at our place over the weekend because it was a decision made by the SIO [senior investigating officer]. There was no referral upwards, and you would have thought on something as sensitive as this there would have been."