The missing: 6,000 people disappear in five years in Wolverhampton

Last year, police recorded 548 missing persons in the city – of which 272 were adults and 276 children – and 1,177 'unauthorised absences'.

This was an increase of 80 missing persons and almost 300 absences.

A missing persons case involves an element of danger, meaning someone could be the victim of crime or could harm themselves or another, while an 'unauthorised absence' is when there is no apparent risk.

In the past five years, Wolverhampton has seen more than 2,000 missing persons and more than 3,000 unauthorised absences.

Chief Inspector Sean Phillips of West Midlands Police said: "We work with the national charity, Missing People to ensure the maximum support and publicity for a missing person and their families.

"We are the largest force to do this and have recorded an increase in the number of families and victims supported through this alliance and a decrease in the length of time a person is missing for by on average half of what it was last year."

In 2012, there were 615 unauthorised absences in Wolverhampton, 444 missing adults and 147 missing children.

Since 2010/11, the number of unauthorised absences for Wolverhampton – and the whole of the West Midlands generally – has increased significantly. For the West Midlands, it jumped from 3,553 in 2010/11 to 8,431 in 2014/15, while Wolverhampton's figures went from 380 to 1,177 over the same time period. Meanwhile, the number of missing persons for the whole of the West Midlands decreased from 15,256 in 2010/11 to 9,049 for 2014/15.

Addressing why there was such a drop off in the number of missing persons but a sharp increase in the number of unauthorized absences, Ch Insp Phillips said: "West Midlands Police adopted the absent policy force-wide in June 2013.

"Since that time reports of missing people were assessed using both criteria for missing and absent, which resulted in some missing reports falling under the new category and as such numbers fell – as expected.

"We are continually reviewing our assessment procedures to ensure the most appropriate responses are being made to each report. This includes training and reviewing the absent definition to ensure any known risks in each case are appropriately assessed in our classification and response.

"Cases that have a particular risk around them are often part of a multi-agency discussion to manage and reduce episodes of missing and any resultant risk of harm they pose."

One of the most high-profile outstanding cases in the Black Country is that of Natalie Putt, the 17-year-old from the Lower Gornal area of Dudley, who has been missing for more than 10 years.

The young mother vanished in September 2003 and has not been seen since.

On the 10 anniversary of her disappearance in 2013, there were renewed appeals for information but her family say they are still no closer to knowing what happened.