The Rehabilitation of Offenders Act 1974 enables the rehabilitation into employment of offenders who have not broken the law again. The Act enables some convictions, cautions, reprimands and final warnings in respect of a particular offence to be considered ‘spent’ after a specified period of time (known as the ‘rehabilitation period’). Convictions which do not carry a custodial sentences, or have a custodial sentence of less than 4 years will have specified rehabilitation periods attached to them, during which period they are referred to as 'unspent convictions' and employers may ask for them to be declared (the e-recruitment system has a check box for individuals to declare unspent convictions).
Once the rehabilitation period has expired the conviction is regarded as spent (provided no further convictions occur within the rehabilitation period). As such, a rehabilitated person can then be treated as if they had never been convicted of the offence and, therefore, are not required to declare any spent caution(s) or conviction(s), when applying for most jobs, unless the post is subject to the exceptions of the Act. Exceptions include, for example, clinical work or particular types of work with children or other vulnerable groups would necessitate the disclosure of ‘spent’ convictions.
A conviction cannot be spent if it carried a custodial sentence of 4 years or more.
A table of rehabilitation periods can be found on the Gov.uk website