But many lawyers were advising clients against making a formal complaint, given that very few were upheld. It was also potentially damaging if clients wanted to sue because this allowed the police access to material denied to the complainant.
However, a recent relaxation of the legal ban on the disclosure of material in a complaints file has led to a significant change in tactics.
"There is now often nothing to lose in making a complaint," says the solicitor Stephen Cragg, co-author with John Harrison of Police Misconduct: Legal Remedies. "The real fears which existed have gone and, in many cases, there is now an advantage to complaining and suing at the same time."
Complainants now have access to the results of the investigation into their case which, if it is carried out thoroughly, can provide valuable material for their civil case, Mr Cragg says.
Cragg and Harrison have just finished updating a third edition of their book, due out shortly, amending their earlier warnings of the dangers of running civil actions and complaints simultaneously.
Across the country, police forces in England and Wales spend more than pounds 30m a year and deploy hundreds of officers dealing with complaints and discipline.
Civilian oversight of complaint investigations is carried out by the Police Complaints Authority. It has dealt with 150,000 in its 10-year history. About one in 10 are upheld annually.
Public interest immunity (PII) - the doctrine that the public interest in preserving confidentiality of some documents can outweigh the public interest in securing justice - has attached to documents generated during a complaint investigation since an Appeal Court ruling in 1981. This was based on the agreement that witnesses would not give statements if they thought they could he used in subsequent civil actions.
However, the result was that the police had access to the material when they were preparing their defence in a civil action - even though they could not use it as the basis of cross examination - but the person suing did not.
The stalemate changed with the case of Wiley, which focused on whether a chief constable was obliged to refrain from using documents produced during the complaints process when defending civil actions. The police lost, fighting the case up to the House of Lords. However, they then changed tack and joined with the complainant and the Police Complaints Authority in arguing that PII should not attach to those documents as a class.
This was upheld by the Law Lords last summer.
Cragg argues it should mean "in theory at least" that fewer guilty officers escape punishment. There was also likely to be an increase in the number of serious complaints being pursued as well as greater scrutiny of the role of the investigating officer and the PCA's supervisory function.
One other effect is that legal aid in civil actions may be extended to cover the preparation of the complaint into the same incident. However, Cragg says the move towards greater openness was followed by a retrenchment by the courts, which decided PII should still attach to the investigating officer's report because it included personal recommendations and conclusions (Taylor v Anderton).
Post-Wiley, lawyers concerned that the police still have the advantage of earlier access to the complaint file have proposed postponing co-operation with the complaints procedure until the stage of exchange of witness statements in the civil case.
However, it is open to the PCA to dispense with the need for an investigation into a complaint if it believes there has been an unreasonable delay. Two recent High Court challenges to PCA decisions on dispensations have failed.
The PCA chairman, Sir Leonard Peach, took issue with lawyers who advised clients to sue rather than complain in his annual report. "Clearly lawyers earn fees from civil actions and their clients are frequently funded from the public purse but they would argue, apparently from disinterested motives, that those who wish to complain are better served by the civil courts."
He said the PCA was at a disadvantage. It could not offer any financial recompense and the level of proof required to "win" a complaint was higher than in a civil case - the criminal standard of beyond reasonable doubt as opposed to the civil standard of balance of probabilities. This could change in some cases under new discipline proposals being negotiated between the Home Office and police.
However, following the Wiley judgement, the gathering of evidence during the complaints procedure was in effect a "free advice" to the complainant's lawyer.
Sir Leonard maintained that, equipped with a finding in the complainant's favour by the PCA or with access to appropriate evidence, he or she was now in an "excellent" position to take their case to the civil courts or to negotiate a settlement without the usual risk or cost.
Fine words but a fundamental misunderstanding of victims' motivation for going to court, according to Raju Bhatt, of Birnberg & Co. "The PCA seems to believe that the motivation of people who sue the police is all to do with money. What they want to see is the officer who had done them wrong being punished. If the complaints investigation was seen to be open, independent and effective, leading to some semblance of justice, then 90 per cent of my clients would not be resorting to the civil courts at all," Bhatt says.
"Wiley does give a greater semblance of a level playing field. However, it doesn't necessarily mean I would advise clients to go through the process. It is an ordeal over which they have very little control and very little chance of success."
John Wadham, legal director of Liberty, also remains critical of the complaints process. "If you sue and the case gets to court, it means the police officer has to defend his or her actions in open court in front of a jury. However, there is then the Kafkaesque situation that a jury can find against an officer, the victim be awarded thousands of pounds in damages and yet the officer is never disciplined.
"If you make a complaint, you are relegated to the position of bystander. Our advice would be only complain if there is a tactical virtue in it for civil action."
Peter Moorhouse, the PCA's deputy chairman, is exasperated by such views.
"Sensible lawyers, who have the interests of their clients at heart, see what the complaints investigation produces first because the letter their client receives from the PCA will be a strong steer as to the strength of the case, there is access to the documents involved and it is a lot quicker than civil action," he says.
He dismisses concern that police lawyers still see the material first. "It's like children exchanging swaps in the playground. There is now disclosure of all the complaints documents and the advantage, if any, for the police has got to be marginal when one is dealing with honest and open witnesses."
At the heart of much distrust of the complaints process is the fact that the police investigate themselves. Cragg, Bhatt and Wadham all argue that the PCA should have its own team of independent investigators.
Moorhouse accepts that it creates a problem of "perception" but maintains that the standard of investigations has always been high, "so why change for cosmetic reassurance? The area where change should be sought is in the outcome of complaints. We have pressed for lawyers to be kept out of the proposed new disciplinary procedures, which include reducing the standard of proof in some cases, until the industrial tribunal stage.
"But there is a considerable danger that the new procedures will still be a lawyers' playground where the truth is bedevilled by delay, adversarial argument and technical submissions," Moorhouse says.
'Police Misconduct: Legal Remedies', Harrison and Cragg, third edition, Legal Action Group, pounds 25.