We didn't need the McAlpine affair to remind us that our era sustains a witch-hunt of which the middle ages might have been proud. Since the late 1970s, successive houndings of supposed paedophiles have done little to prevent the recurrence of the phenomenon. Lord McAlpine got off lightly compared to victims of panics in Cleveland and Orkney, or the people who had their homes besieged by chanting mobs in Portsmouth, or the Newcastle nursery workers subjected to a nine-year campaign of vilification, prosecution, prison violence, mob torment and official denunciation before being cleared of any wrongdoing in 2002. The documentary Witch Hunt, produced and narrated by Sean Penn in 2008, describes a Californian frenzy that saw a carpenter spend 15 years in prison for abuses that never occurred.
The underlying phenomenon is well enough understood.