The Data Protection Act 1998 gives UK citizens the right to access personal information held about them by the criminal justice system. Your local police force has the power to access all information held about you on the Police National Computer. To make a "Police Subject Access Request," you must follow the correct procedure.
Police subject access request
Contact your local police force and tell them you want to access your personal information. Make your request in writing, using the appropriate data protection application form. Some police forces, such as Metropolitan Police, have two data protection forms, one for PNC data and one for local police records. If you want to access your full criminal record, complete both forms. If there is only one form, you will be able to tick the PNC box and also specify in the appropriate section that you want to see your local police records.
Return your completed paperwork to your local police force with proof of your identity, such as a passport, birth certificate or driver's licence, and pay the required application processing fee. If your local police force requires any additional information or proof of identity, they will make this clear to you. You may be asked to provide previous addresses if you've lived in other parts of the UK.
Contact your local police force again if you have not received the information you requested within 40 days.
Under the Data Protection Act, the police are exempt from releasing information in particular circumstances, such as when doing so "would be likely to prejudice the prevention or detection of crime" in an ongoing investigation.