Detectives have marked the 15th anniversary of the disappearance of university chef Claudia Lawrence with a plea for those with information to break their silence.

Ms Lawrence was reported missing after she failed to report for work at York University in March 2009.

Her disappearance has been treated as a murder inquiry by North Yorkshire Police almost from the start, and the case had become one of the best-known unsolved crimes of the last 20 years.

On Monday, Acting Assistant Chief Constable Wayne Fox insisted the inquiry was not closed.

Mr Fox said: “Having been appointed senior investigating officer in October 2020, I am fully aware of the complexities that exist in this inquiry, which sadly has to be treated as that of a suspected murder.

“However, the single barrier to unlocking the answers for Claudia’s loved-ones and bringing those responsible for her disappearance to justice, remains the same – silence.

“Silence from the people who know, or may suspect, what happened to Claudia but have, so far, for reasons that are only known to them, been unable to come forward to the police or even pass on information to Crimestoppers anonymously.

“There may be many reasons as to why they have been unable to come forward, however, my plea to them on reaching 15 years of living with the knowledge you have is to do the right thing and make a report.

“You can help bring an end to the pain and uncertainty for Claudia, her mum and all who love her.”

North Yorkshire Police has conducted two investigations and questioned nine people but no charges have ever been brought.

For such pain and despair to continue for 15 years without knowing where your child is, or what happened to them, well that is far beyond what any mum or dad should ever have to live with

The last major police operation in the relation to the case was in 2021 when officers spent a number of days conducting an extensive search of flooded gravel pits at Sand Hutton, near York.

Mr Fox said the investigation has been in a “reactive phase” since 2017 but he said: “I again want to make it clear that the investigation is not closed.

“Even after such a passage of time, our Cold Case Review Unit continues to receive information.

“Every new piece of information is carefully assessed against the significant volumes of material that has been gathered over the full course of the investigation.”

He said the scale of the 2021 operation “clearly demonstrates that, if information is capable of being effectively developed, North Yorkshire Police will work tirelessly in our continued search for the truth.”

Mr Fox said: “Speaking purely as a parent, my thoughts as we enter the 15th year since Claudia Lawrence was reported missing, remain with her mum Joan. I cannot begin to understand the pain that Joan and her family feel every single day.

“For such pain and despair to continue for 15 years without knowing where your child is, or what happened to them, well that is far beyond what any mum or dad should ever have to live with.

“Joan has lived with unending uncertainty and trauma since the last conversation she had with Claudia on the telephone on the evening of March 18 2009.”

Mr Fox said he was also thinking of Ms Lawrence’s father Peter, who campaigned for his daughter to be found, but died three years ago without ever knowing what happened to her.

Ms Lawrence was 35 when she went missing and would have celebrated her 50th birthday in February.

Mr Fox said: “That she has been denied the opportunity of fulfilling her potential and living life in a way that made her happy, be that in career aspiration, travelling the world or the possibility of raising children, is tragic in the extreme.

“Let us not forget that Claudia’s family and closest friends have also been denied the opportunity of living and sharing these types of momentous moments with her. That is equally sad and can surely only magnify the pain that they continue to feel 15 years on.”