[Nini74] "Are you seriously advocating lying to a potential employer?"
Chris is not offering an opinion, he is restating a fact which has been in place for four decades - it is UK legislation which is advocating 'lying' to a potential employer.
The Rehabilitation of Offenders Act 1974 exists to support the rehabilitation into employment of reformed offenders who have stayed on the right side of the law.
Under the Act, following a specified period of time which varies according to the disposal administered or sentence passed, all cautions and convictions (except those resulting in prison sentences of over 30 months) are regarded as ‘spent’. As a result the offender is regarded as rehabilitated.
For most purposes the Act treats a rehabilitated person as if he or she had never committed an offence and, as such, they are not obliged to declare their caution(s) or conviction(s), for example, when applying for employment or insurance.
Once a caution or conviction has become spent under the Act, the ex-offender does not have to reveal it or admit its existence in most circumstances. There are some exceptions, but unless you are told one of these applies and are asked for more details of all your cautions or convictions, spent cautions and convictions need not be disclosed when filling in a form, or at an interview, for instance for a job. An employer cannot refuse to employ someone (or dismiss someone) because he or she has a spent caution or conviction unless an exception applies.
The exceptions where you may have to declare spent cautions and convictions are listed on the Rehabilitation of Offenders Act 1974 (Exceptions) Order.
http://www.justice.gov.uk/downloads/offenders/rehabilitation/rehabilitation-offenders.pdf