Murder squad detectives have received so much information in the hunt for Claudia Lawrence they have had to overhaul their entire archive system to meet recommendations drawn up by an independent inquiry.

The National Policing Improvement Agency (NPIA) was commissioned by North Yorkshire Police in May to carry out a second review of how the inquiry had been handled.

Newly published recommendations included an overhaul of administrative procedures relating to the “management of processing, and categorisation” of the details collated during the investigation.

Assistant chief constable Tim Madgwick said the issues had now been addressed and had not affected the outcome of any lines of investigation.

The search for the missing University of York chef is one of North Yorkshire’s Police’s biggest-ever cases, and concerns have been raised over whether the inquiry team had been swamped by information.

The external review has seen a restructure of an archive containing details of more than 5,300 calls, searches, statements and reports.

Friends of Claudia, who was last seen walking near her Heworth home in March last year, have maintained that members of the public who made reports were never contacted again.

Martin Dales, a close friend of Claudia’s father, Peter, said: “Resources were obviously stretched in such a major investigation, especially with one that has received such a high profile in the media.

“But this can prove to be a double-edged sword, as the police have to contend with a surge of information in the wake of any such publicity.”

He said the public needed to be reassured that the inquiry had been handled properly but said people who reported information that could have resulted in potential new leads were not contacted by the force for weeks or months, if at all.

The NPIA was brought in to carry out an initial reviews of the investigation last year and the inquiry team was advised to focus more attention on Claudia’s private life.

Senior detectives admitted the investigation has been hindered by the chef’s complex relationships, as she sometimes had more than one lover at a time.

Mr Madgwick stressed the second review had also found the investigation had been conducted with “integrity and objectivity” and strategies conformed to nationally approved standards.

The review team made a suggestion for a minor line of inquiry, details of which have not been disclosed, although it has not led to any development in search of Claudia.

Mr Madgwick said: “North Yorkshire Police remain as committed as ever to solving Claudia’s disappearance and bringing closure to the family. Both reviews were commissioned voluntarily and can been seen as a demonstration of our commitment to ensure that no stone is left unturned in our drive to find out what has happened to Claudia.”