Every police station in the country has at least one HOLMES suite. This is the Home Office Large Major Enquiry System, which allows computer-illiterate coppers to join the late twentieth century. Getting them to join the twenty-first century would be too much to ask for.
Everything related to a major investigation is kept on the system, allowing detectives to cross-reference data and avoid the kind of cock-up that made the hunt for the Yorkshire Ripper such an exemplary operation. The replacement to the old system was due to be called SHERLOCK, but nobody could find the words to make the acronym work so they called it HOLMES 2.
You don’t get to use HOLMES for every day crime that’s what AWARE is for, as MERLIN is anything to do with kids, CRIS is for crime reports and ENCOW is for training programmes. The POLICE NATIONAL COMPUTER (PNC) is something else entirely. When you log in into HOLMES you have to use your warrant number which means the operators can track you make an unauthorised inquiry.