NO SELF-RESPECTING member of society can tolerate abuse of children, but how far should we go in investigating it? And what are the risks of innocent people being drawn into the net?

Northumbria Police have recently employed an unusual investigative tactic which has become known as the "trawling" method whereby officers actively go in search of allegations by contacting former care residents. Trawling is currently employed by 32 forces countrywide in more than 80 operations. But campaigners claim the technique is seriously flawed.

Chris Saltrese, a solicitor representing the accused from a similar operation run by Merseyside Police, said: "It is highly dangerous, improper, unethical and disastrous for innocent people and highly wasteful in terms of public resources. You are talking nationally about hundreds of millions of pounds being thrown down the drain."

Mr Saltrese is not alone in his concern. Judge Johnathan Crabtree said at a trial this year: "Police forces that have fished for allegations of sexual abuse are in danger of garnering false allegations."

Concern has led to the creation of more than a dozen campaign groups nationwide, all clamouring for Home Secretary Jack Straw to review such methods of policing. One association, Falsely Accused Carers and Teachers (FACT), includes solicitors, barristers and academics among its members.

A spokesman said: "We believe police trawling methods inevitably lead to false allegations, in most cases fuelled by the attractions of large compensation payments in the event of a guilty conviction. False allegations of this nature have devastated the lives of thousands of present and former careworkers and teachers and their families."

It is understood that between 20 and 25 abuse cases undertaken by Northumbria Police have reached the courts in the past three years. A handful of these have resulted in convictions. Ivan Oliver, a social worker, admitted in March 1998 to having sex sessions with a 15-year-old schoolgirl he met while working in a Northumberland care home. In May this year, former Newcastle care home worker John Healy was found guilty of molesting two girls in his care. But operational successes cannot mask a rash of acquittals.

This year alone, 11 care workers in five cases walked free from court - their charges cleared, but their names and reputations irreparably damaged.

Northumbria Police's trawling method has resulted in the suspension of a number of care workers. Nearly all have yet to have those suspensions reversed - despite being acquitted.

All the suspended workers have been banned from speaking to the media.

According to the campaign group Action Against False Allegations of Abuse (AAFAA), this prevents the truth coming out.

A spokesperson said: "They cannot speak. This is what keeps the whole sorry situation so damn secretive. Even though they have been cleared, these people are still painted as paedophiles. What people say is they still feel dirty. You remain humiliated.These cases should just not have got to court."

Northumbria Police refuse to release details of how their investigation is progressing. They will not say how much the investigation has cost, how many people have been accused, how many complainants there have been, or how many convictions and acquittals have occurred.

The real question is what effect will trawling have on future abuse allegations?

Mr Saltrese said: "I am not saying all former residents are going to tell lies. I also acknowledge that abuse has gone on in these homes. I have spoken to men who have admitted it. But some of these allegations are effectively debasing genuine ones. In three or four years time, if someone comes forward, it is likely they will not be believed.