On 10 March 2014 the Rehabilitation of Offenders Act 1974 was amended to reduce the rehabilitation periods that must expire before  those convicted of certain crimes can treat them as spent and not disclose them to potential  employers. The definition of those designated as the most serious offenders (who will always be required to disclose their criminal record) has also been changed to cover those receiving  prison sentences in excess of four years rather than two and a half years. Certain specified sexual  or violent offences will still never become spent.