ABHORRENCE of paedophilia makes it difficult to have a dispassionate discussion about alleged child abuse.

This week has witnessed a rising tide of hysteria around the issue, with the names of scores of alleged abusers swirling around the internet. The impression given by some commentators is that child sex abuse exists in every community up and down the country.

This has generated more heat than light. The catalyst was the revelations about Jimmy Savile. It is now abundantly clear that this apparently affable loon was a dangerous fraud, a Jekyll and Hyde character who preyed on young people, some of whom were made to feel like worthless trash. Their misery has been compounded in some cases because their original allegations were not taken seriously.

However, in the rush to judgment in this case, a mass of other unrelated allegations have resurfaced, some of which are little more than wild rumours, without any foundation. Yesterday, Lord McAlpine, who has been widely named on the internet and whose home in Italy has been besieged by reporters, announced that he has no choice but to take legal action over what he called false and seriously defamatory statements about him. It was reported yesterday that the peer, a former Conservative Party treasurer, was the victim of mistaken identity.

Confronted with a list of suspected abusers harvested from the internet, the Prime Minister was right to say that serious allegations should be reported to the police and that meanwhile there is a danger that what began as a legitimate journalistic investigation risks turning into a witchhunt against gay men.

The suggestion that there was a paedophile ring among senior Tories during the Thatcher era is not new but evidence is at best flimsy. When hysteria takes hold of such an allegation, truth tends to be an early casualty. Arthur Miller's play The Crucible about the Salem witch trials shows what can happen when one accusation breeds another.

In real life too, the lessons of the Orkney and Nottingham child abuse cases are that innocent lives can be destroyed by false allegations. In the current febrile atmosphere, it is important not to switch off our critical faculties. Today there are rigorous procedures to guard against the contamination of juvenile testimony by lurid suggestion, but none of these safeguards applies to the past, which is why caution is required.

Those who seek to highlight child abuse do not help their cause by drawing the definition so wide as to suggest that nearly a quarter of children are victims. Conflating what many regard as old-fashioned parenting – the occasional smack or asking children to do chores – with serious beatings, torture and rape, is a disservice to those who desperately need help.