I was 15 when I met Cliff Richard.

I was a pupil at a boys only boarding school. Every Sunday – this was back in the 1970s – we all had to attend a religious service. Mostly these took place in the school’s wonderful chapel but every so often speakers were invited to give a religious talk in a more secular setting. One of these was Cliff.

He was a star, albeit no longer a very trendy one, and there was great excitement as the day of his visit approached. Not only would the great man sing, play his guitar and entertain us in his characteristic happy-clappy-Jesus-loves-you sort of way, he would also answer questions, so it was said, “about anything you like.”

Of course nobody would have dared ask him about his sexuality. You didn’t ask visiting speakers about such things and – even though we were all, of course, pretty obsessed by sex in general – I don’t remember any particular interest being expressed in Cliff’s sex life. Instead, encouraged by the promise of a no-holds-barred debate, I went to the meeting, shyly prepared to bowl him a deistic doosra. “Why does a perfectly good God allow famines?” or some such enigma.

Sadly I never got the chance to cross-examine the great man, or even to try out my question. Cliff set himself up on stage and displayed no apparent desire to hob-nob with any of the hundreds of star-struck adolescent boys. Indeed, as far as I could see he tried to insulate himself from any direct contact with us at all. Instead of engaging directly with the seething mass of teenagers gathered in the hall, all questions were “moderated” through a trusted side-kick who announced that the only questions allowed would be those posed to Cliff by him, on our behalf.

So it was all a bit of a disappointment. Cliff strummed his guitar, thumped his tambourine and crooned out a few gospel numbers while running through an obviously rehearsed catechism routine with his assistant. Even though we’d not had to shell out our pocket money to listen to him, I think most of us came away feeling slightly short-changed. There were no conversions, healings or speakings in tongues, and at least one member of the audience left the hall very slightly disillusioned about the Christianity that Cliff clearly believed in so strongly. The best that can be said is that he made absolutely no attempt to molest me, or indeed anybody else.

I daresay that rather dreary Sunday morning session made considerably less of an impact on Cliff than it did on me. In fact, it wouldn’t surprise me if he’d entirely forgotten coming to the school.

I was reminded of the event when I read that “a number of people” had “provided information” after the recent heavily publicised search of Cliff’s apartment. We do not know, of course, of what the information consisted, nor why those in possession of it had not gone to the police before publicity was given to the raid, nor whether it was accurate.

South Yorkshire Police are in dispute with the BBC about precisely how the leaking of details of the raid came about, but one suggestion often made is that such publicity is justified if it encourages more “victims” to “come forward”. The vivid metaphor used by Geoffery Robertson QC in a coruscating attack on the police tactics, is that they were “shaking the tree” to see if further witnesses would come forward once they heard that an investigation was under way.

If that was indeed their plan then it was exceptionally ill-advised. Shaking a tree might produce some tasty plums, but it will also guarantee you the rotten ones. Genuine witnesses might indeed be emboldened by the news that Cliff was under suspicion, but so too would malevolent ones.

It is, of course, true that many people who are sexually abused are too frightened or too traumatised to go to the police for many years. It is also true that false complaints are sometimes made. The difficulty is in trying to distinguish between the true and the false, when many years have passed.

Disapproval of sexual offending, hatred of rapists and detestation of child abusers are all beside the point. A concern that some people might not get a fair trial does not equate to a belief that child abuse doesn’t matter. The same questions arise if a person is accused, many years after the event, of the sort of offence that does not engender such strong disapproval: burglary, say, or armed robbery.

Back to Cliff. If I had a pressing need for money I would have a motive, and if I was of a dishonest disposition my meeting with Cliff in the 1970s could now provide me with an opportunity. I would feel emboldened by the announcement that another man has apparently made a sexual complaint against him.

Road accident insurance scams are now acknowledged to be big business. According to the Association of British Insurers, fraudulent car crash claims cost the industry £1.3bn in 2013. Typically the fraudster will slam on his brakes in front of an unsuspecting motorist. “Witnesses” are sometimes on hand to shore up the fraudulent claim, which generally involve spurious but hard to refute claims of whiplash injuries.

Some cases are detected, but obviously many are not. One North-East family alone is said to have obtained over £3,000,000 by the fraud until it was stopped.

Given that false claims of road accidents are made on an industrial scale, it would be strange if there were no fraudsters making false claims of sexual abuse. As to the scale of the problem: as with so much in this area of the law, it is anyone’s guess.

The sums involved are not trivial. If it is public money you are after, the Criminal Injuries Compensation Authority’s £27,000 for a childhood rape leading to serious mental illness may be insultingly low, but £1,000 for what it calls “a minor non-penetrative act over clothing” might be rather more tempting, although the rules governing eligibility are extremely strict.

For those prepared to take their chances in the civil courts the sums are much higher: £40,000 – £50,000 would be the going rate for, say, repeated non-penetrative abuse by a schoolmaster over a period of a few years, although if you can show serious psychiatric harm your damages could run into millions. As with any civil case, there are risks; primarily that you might have to pay the other side’s costs if you lose; and also that you might be prosecuted if your claim is proved to be false. The latter seems a remote risk.

If your chosen defendant is dead, of course, your chances of success are even better. It’s your word against his and the dead can’t talk.

Public figures, dead or alive, are at particular risk of false claims. Not only is there the incentive of civil damages, there is also money to be made from selling salacious information.

Nobody in public life is immune from the danger of malicious allegations. The Prince of Wales was the victim of a false claim implicating him in a sexual incident with a Royal servant. Seven months later, the source of the story, royal valet George Smith, admitted that the “sex scandal” had been an invention for which he was paid £60,000 by a Sunday newspaper.

Former MP Neil and his wife Christine Hamilton were targeted by 29 year old Nadine Milroy-Sloane, who mainly “out of a desire for financial reward and celebrity status“. accused them of a catalogue of sexual and other offences, including involvement in raping her. Advised, ironically enough, by Max Clifford (who had apparently told her that the allegations could net her £100,000) Miss Milroy-Sloane complained to the police who duly arrested the Hamiltons. Not until sometime after they produced a cast-iron alibi for the date in question did she withdraw her allegation.

Milroy-Sloane’s “mistake” was to allege a relatively recent attack. Not only did she have to undergo an unpleasant forensic medical examination but, by choosing a specific date, she gave the Hamiltons an opportunity to prove their innocence. Fortunately for them Mrs Hamilton was able to produce a sheaf of receipts to prove their alibi.

Almost invariably those accused of historic sexual crimes have no such opportunity. Even if complainants give specific dates (which for obvious reasons, and whether or not they are telling the truth, they hardly ever do) the chances that a defendant would be able to prove what he was doing, still less what he was not doing, on a particular day 30 or 40 years ago are extremely remote. It is all very well saying that the burden of proof is on the prosecution: where there is no proof beyond the say-so of witnesses the potential for injustice is huge. Psychological studies suggest that most people are able to identify liars in only just over 50% of instances, meaning that where cases depend exclusively on the evidence of a single witness, rather than, say, scientific evidence juries are almost inevitably going to make mistakes.

Witnesses can also make mistakes. Katrina Fairlie, for example, falsely accused her father, the deputy leader of the Scottish National Party, and 17 other men of a series of sexual and violent offences including rape and murder. She had no obvious financial motive to lie but it later emerged that her false memory had emerged during therapy with a respected consultant psychiatrist.

Historic sexual cases are brought as a result of adults claiming to remember incidents that happened to them in childhood. There is a particular danger here: the more specific and detailed such allegations are, the more credible they seem to juries¹, despite there being no correlation between the recollection of trivial details and accuracy of memory. Indeed, the apparent recollection of trivial details from early childhood is probably more indicative of a false than of a genuine memory². Thus, a mistaken or dishonest witness who includes plenty of invented details about a childhood incident will be both more likely to be wrong and more likely to be believed than an honest defendant who – perfectly naturally – cannot remember what happened 30 years ago.

Sexual cases differ in practice, if not in principle, from almost all other types of crime. It is virtually unheard of for a prosecution to be brought decades after the alleged crime in any other category of case except homicide. And homicides are unlikely to depend exclusively on the recollection or honesty of witnesses. If a mummified body is found after 30 years it may still be possible to glean a good deal of evidence. A broken neck bone might indicate strangling, or a distinctive rib injury might suggest a stabbing. Fragments of clothing or even blood stains can be forensically examined. Bank accounts and insurance documents can provide evidence of financial motive, and so on. At the very least there is likely to be strong independent evidence that a murder has taken place. A murder case that depended upon the uncorroborated word of a single witness deciding to “come forward” after 40 years would be a very curious thing.

An allegation of historic sexual abuse, on the other hand, may well have no supporting evidence at all. Without the word of the alleged victim there is usually no evidence that it even occurred.

It is in such circumstances that the practice of “shaking the tree” can become particularly dangerous. A single uncorroborated allegation may not be very persuasive. But publicising the fact that one has been made can encourage further allegations, each individually dubious, but together acquiring a specious flavour of credibility. It is an approach described by Mr Justice Eady in Lillie and Reed v. Newcastle City Council & others (an extraordinary case where a Local Authority review panel convinced itself, in the teeth of evidence to the contrary, that a paedophile ring was operating in one of its nursery schools) as “sloppy.” Lurid rumours and false assumptions spread through parents and the Council alike, leading to what the judge described as a “feeding frenzy” of injustice.

What is more, a failure to rebut any of the spurious allegations can itself seem somehow to support their truth, whilst an unsuccessful attempt to do so – for example to set up an alibi that is then destroyed – will be taken as a very black mark against any defendant. Rolf Harris’s defence appeared to crumble after he was shown to have appeared on a television show in Cambridge when he had stoutly maintained that he had never been to the city.

Unlike many European countries and the United States, English law has never had a general statute of criminal limitation, the principle being that time should not run against the sovereign (“nullus tempus occurrit regi,” for those that enjoy Latin). Nevertheless, until relatively recently the law placed a number of obstacles against ancient allegations being raised. Evidence of “bad character” was not permitted. Juries were asked to look for corroboration. Cases would sometimes be stayed where the passage of time meant a fair trial was impossible. Prosecutors would not bring a case unless they thought there was a better than 50% chance of a conviction. One by one those obstacles or, as they were once quaintly called, “safeguards”, have been swept away entirely, or at least greatly diminished.

Lord Woolf, a former Master of the Rolls and Lord Chief Justice, was prescient enough to foresee danger ahead in 2001, when he warned that plans to change the law to allow evidence of bad character to be be introduced more routinely might lead to injustice. He was ignored and the law was changed to allow evidence of “propensity” to be given far more easily. Instead of merely permitting the prosecution to present evidence of previous convictions the law now allows a number of unproven allegations to be treated as “mutually corroborative,” in effect, if not in theory, allowing juries to accept the argument that there is “no smoke without fire.”

Juries used to be warned that it was “dangerous” to convict on the uncorroborated evidence of a complainant in a sexual case. Because the warning was confined to sexual allegations it was rightly considered insulting and absurd. Nevertheless, a warning to look for corroboration in every case – Scots law still sensibly requires it as a matter of law⁴ – would at least be some safeguard when dealing with historic allegations. All that remains is a rather woolly general warning about possible unfairness to the defence where there has been a long delay.

The argument that delay can amount to an “abuse of process” is virtually a dead letter. After some uncertainty the Court of Appeal has decided that delay, even of thirty, forty or fifty years and with no explanation, is not, in itself, a reason for staying a case⁵. In theory, judges can still stay prosecutions where the delay has caused unfairness to an accused; in practice any such arguments are almost always met by the retort that the trial process itself is the place to deal with any perceived unfairness. Juries are then told that they can be the judge of which witnesses are telling the truth, when in fact the delay itself has rendered such a task all but impossible.

The Crown Prosecution Service is now much readier to prosecute all sexual allegations than it was. The current DPP, Alison Saunders, has endorsed the practice whereby prosecutions can be brought in sexual cases even when everyone expects the jury to acquit, provided that in its view a “notional” objective jury would convict. This is how she explains it:

“Even though past experience might tell a prosecutor that juries can be unwilling to convict in cases where, for example, there has been a lengthy delay in reporting the offence or the complainant had been drinking at the time the rape was committed, these sorts of prejudices against complainants should be ignored for the purposes of deciding whether or not there is a realistic prospect of conviction. In other words, the prosecutor should proceed on the basis of a notional jury which is wholly unaffected by any myths or stereotypes of the type which, sadly, still have a degree of prevalence in some quarters.”

When weak cases are brought, of course, many of them fail. Many are cases that would never previously have been brought to court. But some, perhaps to everyone’s surprise, succeed.

Those who would blame Ms Saunders for adopting this approach – and I admit to having questioned the policy myself – are not being entirely fair. The matter has been taken out if its hands. Since the case of R. (on the application of B) v. DPP⁶the Crown Prosecution Service’s previous approach of only bringing cases it expected to win has been ruled unlawful. Nor, when one thinks about it, is it always wrong to prosecute despite expecting to lose. Would it be right for the CPS to refuse to bring a prosecution because it anticipated that a jury was likely to divide, say, along racial lines? Nevertheless, whether it is right or wrong, it is a policy that has led to more prosecutions and thus, inevitably, to more convictions.

So back to Cliff Richard. I now have the perfect opportunity to present myself as a victim and solve some financial problems. I could go to the police alleging that after his dreary talk Cliff indecently assaulted me. I can surmise that there is at least one other complaint from a teenage boy – because the police or the BBC or both have already publicised the fact. I can dredge up all sorts of details from the depths of my memory – or imagination – that might give it the ring of truth. It would be a lie, but who would know? If Cliff has forgotten that he ever came to my school (which is perfectly possible), so much the better. His denial might be uncovered, he would be seen as a liar and I would be vindicated. What is more, save in the unlikely event that a prosecution was brought against me, I could not be publicly named, whatever the result of any trial.

Something has gone badly wrong here. Nobody wants those who have committed serious sexual offences to avoid punishment. On the other hand, the current vogue for prosecuting men for offences allegedly committed against children more than a decade ago; and to do so in some cases where corroboration is either weak or non-existent has all the potential to produce miscarriages of justice on a scale unprecedented in recent English history. According to the Justice Secretary Chris Grayling, the main reason for our prisons now being over-crowded (or as he would prefer to put it “under pressure”) has been the imprisonment of “hundreds of inmates convicted of sex offences after the Jimmy Savile scandal.”

No doubt many of these men are indeed guilty. To say that some witnesses lie or are mistaken is not to say that all, or even that most are.

No sensible person doubts that sexual abuse of children is a real and serious issue, nor that the police and “authorities” generally have – as in Rotheram in the last twenty years, sometimes preferred to ignore the issue even when presented with powerful near contemporaneous evidence. But it is precisely because the issue is so serious and so emotive that we need to be especially careful to ensure that historic cases are only brought when the evidence is strong. Bringing weak historic cases in the hope that uncorroborated complainants will be believed is a recipe for injustice. Verdicts will be based not on hard evidence but on impressions, guesswork and prejudice.

In the late 1970s and 1980s widespread anger at Irish Republican terrorism combined with over-enthusiastic policing, sloppy forensic science and a complacent judiciary to produce a whole series of miscarriages of justice. That did not mean that everyone convicted of terrorist offences was innocent. Looking back, however, it is perfectly obvious that Irishmen accused of terrorist offences were often denied a fair trial.

There is a grave danger that in its zeal to demonstrate our disapproval of sexual offences against children our legal system is now systematically denying justice to old men.