most crimes are "spent" after a period (usually 6 years, depending on the crime) but certain crimes are never spent - murder, rape, child offences to name a few. Also when joining certain professions (police, teaching, child care) then ALL crimes (no matter how long ago they were committed) have to be declared. Although you may think a burglary charge of 10 years ago is spent, but the police will still hold the crime on record, and will declare it when asked (certainly they will do a check themselves, also they will be asked by certain professions for a police check). You should come clean at the interview but at the end of the day then I'm afraid with a previous for serious assault you will not likely be considered for a career in the police force. ps. i'd work on your spelling and grammar as a GCSE in English is a requirement.