Rising numbers of people are going missing, with police now receiving more than 800 reports every day, new figures show.
Forces in England, Wales and Scotland logged a total of 315,517 calls about people disappearing in 2014/15.
The figure, which was up from 307,418 in the previous 12 months, means police are handling more than 6,000 missing persons reports each week and 864 daily.
Prior to 2013/14, there had been a steady fall in numbers.
A spokeswoman for the National Crime Agency's UK Missing Persons Bureau said the year-on-year increase in reports was relatively small, at less than 3%.
She added: "However, there are likely to be a number of factors including improvements in the way the data is collected by police forces and the quality of the data supplied to UKMPB.
"It is also possible that there have been improvements in reporting cases by the public to police. We are now in the process of conducting further analysis to draw more comprehensive conclusions."
More detailed data for the 43 forces in England and Wales shows that the total of 275,000 calls related to 137,000 individuals, with many cases involving people going missing on multiple occasions.
Children and teenagers account for more than half of all episodes (54%), while the data shows that three quarters of calls are resolved within a day, and 85% within 48 hours.
Analysis of records from 20 police areas indicates that the vast majority (96%) of those reported missing are found safe and well.
One in thirty (3.3%) were hurt or harmed, 0.3% were victims of sexual offences and 0.4% were found dead.
Joe Apps, head of the bureau, added:"These figures offer an important insight and demonstrate that we need to keep striving to understand the reasons why people go missing in the first place.
"Fortunately the vast majority of cases are resolved quickly and result in people returning safe and well, however we should remember that each involves an individual and can cause great distress to their loved ones.
"Missing episodes can be indicators of other vulnerabilities - including mental health issues, physical abuse or sexual exploitation, so we need to maximise our efforts to keep vulnerable people safe and support those affected by missing events.
"NCA UKMPB and police continue to engage in preventative work alongside the public and voluntary sector, particularly with regard to working with those who go missing on repeat occasions."