The Interpol Missing Persons Register lists people missing across the globe. These are given the tag of yellow notices. You can narrow the search down to UK nationals by selecting it as an option from the search tool. At the time of writing there are currently 68 individuals with UK citizenship listed. In total there are 1300+ missing in the registry.
There are many features available in a standard search. These include first and last names, nationality, current age, sex, eye colour, hair colour and keywords. You can also select identity unknown and use features instead. The results provide details of those meeting the criteria. Each one has a profile and commonly a photo. It provides information such as the date and location of the disappearance as well as the persons particulars.
If you should have any information as to the whereabouts of someone in the Interpol Missing Persons register, you should contact local and national police, or Interpol.