An obvious example is the horrible Soham murders, in which a man, Huntley, murdered two schoolgirls whom he only knew through their association with his girlfriend. The man was caught and convicted, and is highly unlikely ever to be released from prison. There was a crime, the law took its course, the victims' families mourned, and the press pumped up its circulation on the back of the case.
But none of that represents the real impact of the case. Prior to Soham the Rehabilitation of Offenders Act 1974
laid down the commendable principle that for all but the most serious crimes a period of good behaviour would allow an offender to act as if the conviction had never happened; for many offenders crime is something they grow out of, and they take their place in society when they have done so. But after Soham pressure from the press and from public opinion led to the erection of the whole CRB culture, and the effective collapse of the ROA regime.
The nub of the Act is in this (edited) extract:-
where an individual has been convicted, whether before or after the commencement of this Act, of any offence or offences, and the following conditions are satisfied, that is to say—
(a)he did not have imposed on him in respect of that conviction a sentence which is excluded from rehabilitation under this Act; and
(b)he has not had imposed on him in respect of a subsequent conviction during the rehabilitation period applicable to the first-mentioned conviction in accordance with section 6 below a sentence which is excluded from rehabilitation under this Act;
then, after the end of the rehabilitation period so applicable (including, where appropriate, any extension under section 6(4) below of the period originally applicable to the first-mentioned conviction) or, where that rehabilitation period ended before the commencement of this Act, after the commencement of this Act, that individual shall for the purposes of this Act be treated as a rehabilitated person in respect of the first-mentioned conviction and that conviction shall for those purposes be treated as spent.
Inevitable mission creep over time has led to a CRB check system that allows for an enhanced, full, check in certain circumstances, that will reveal all convictions however ancient. It isn't too difficult for a determined employer to justify the need for a check - for example any company that supplies goods or services to, say, an old people's home or a school can check up on whom it is hiring in direct contradiction of the spirit of the ROA. Many years ago I used to do business with a firm in the hospitality industry, and they checked the police record of every single employee by the simple expedient of paying police officers for the information.
So a young person who, say, steals a bike in a moment of drunken idiocy might find that conviction for theft emerging 25 years later when he is applying for a senior post in a sensitive area.
Without Huntley, it's perfectly possible that none of this would have happened.
The other case that comes to mind is R v Witchelo (1992) 13 Cr.App.R.S. 371. This was the case of a man who elaborately tampered with goods on supermarket shelves in an attempt to blackmail the store owners. He was caught and got a stiff 17 years pour encourager les autres. The long-term effect of that case is the introduction of elaborate tamper proof seals on food packaging, so that every time we buy a jar of jam or some such we pay a few pence towards the cost of the seals, as well as suffering the frustration of trying to open the package. Witchelo has probably cost the UK economy as much as a medium-sized earthquake over time, and the costs will run on and on for ever.