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Which is better: adversarial or inquisitorial?

27 Apr 2023

| Author: Leslie Thomas KC

So, which is better: the adversarial system or the inquisitorial system? Many people have strong views on this question. The Australian judge, Ray Finkelstein, argues that the adversarial system is bad at discovering the truth. He says, “…the parties’ self-interest does not aid the search for truth in a system where it is routine:

  • for opposing testimony to be discredited regardless of whether it is true or not;
  • for the incompetence of opposing counsel to be exploited;
  • for material facts to be omitted from pleadings or withheld due to privilege;
  • for probative evidence to be excluded; or
  • for counsel to indulge in sophistry and rhetorical manipulation of which the primary aim is to obscure the truth.”

Finkelstein’s arguments are focused on civil cases. He recommends several reforms. He calls for judges to have a more active role, including the power to call a witness where the interests of justice so require, the ability to question witnesses beyond their present restricted role and primary control over the questioning of witnesses. He also calls for judges to have the power, in appropriate cases, to appoint an independent examiner to question witnesses prior to trial. And he calls for the court to control the appointment of expert witnesses.

However, it is in the context of criminal cases where the adversarial versus inquisitorial debate tends to be most heated. Richard Lomax, in his report Reforming Justice for the charity Toynbee Hall, robustly argues that the inquisitorial system of criminal justice is superior to the adversarial system. He argues that significantly more resources are expended on criminal defence in the English and Welsh adversarial system than in continental European inquisitorial systems. He states that the cost of legal aid in England and Wales is about 15 times the European median and that while the European median for the cost of defence is about 25% of the cost of prosecution, in England and Wales it is nearly 400% more.

By contrast, he says, “We spend significantly less on police, prosecutors and on professional judges. Evidence gatherers, case presenters and assessors of evidence in comparative terms are all starved of resources.” He goes on to argue that England and Wales and other common law systems tend to have higher rates of imprisonment per capita than European civil law systems.

Lomax argues that “inquisitorial trials are capable of working much faster, giving rise to higher conviction rates, higher public confidence and less probability of being distracted by irrelevant considerations”. Pausing there, we might wonder why Lomax sees higher conviction rates as a good thing. But he addresses this in a footnote, where he asserts, “It would be an error to imagine that continental courts are all biased. Their systems commence fewer weak cases and allocate the necessary resources to those that they prosecute.”

He goes on to argue that the adversarial model means a lower probability of the truth being discovered, meaning there are greater prospects of the innocent being wrongly convicted and the guilty being wrongly acquitted. He argues that to maintain the principle of deterrence, adversarial systems must punish more severely, which he says is why these systems tend to have higher prison populations.

So, is Lomax right that inquisitorial systems are better at getting to the truth? There are perhaps reasons to be sceptical about whether judicial supervision of the investigation makes the process any fairer. Jacqueline Hodgson, an academic at the University of Warwick who has written extensively on the differences between the British and French justice systems, told the Select Committee on European Union in 2005:

“My own empirical research in this area suggests that suspects in France are just as vulnerable to the hostility of the police environment as in England and Wales. Judicial supervision in most instances is conducted by the procureur (the prosecutor, who also enjoys a judicial status as a magistrat) and exists as a form of bureaucratic and retrospective review: the police are required to inform the procureur of a suspect’s detention in custody and the file is later reviewed. The procureur remains in her office and is responsible for supervising tens of cases at any one time. Whilst this procedure is able to weed out obviously weak cases early on, and to review the outcome of investigations, it provides no real guarantee as to the reliability of the evidence gathered. The process of investigation and evidence gathering is shielded from scrutiny.”

In a 2001 article, in which Hodgson reported findings from an empirical study of the French pre-trial process, she described how French procureurs, the prosecutors who oversee most pre-trial investigations, were tolerant of aggressive questioning by police to pressure suspects to confess. She described a “general tolerance… of the kinds of pressure that the police might need to exert to make the suspect tell ‘the truth’. And the crime control ideology of the procureur means that in most instances, ‘the truth’ is a confession”.

She described a lack of interest in investigating whether the police had abused suspects: “In one area observed there was concern that suspects were being brought to court bloodstained and untidy. The police were instructed by the procureur that this was not acceptable and that it did not look good before the court. No enquiry was made, however, into why suspects arrived in this state.” She went on to say, “Even questioning which might be classed as overbearing or oppressive by a British court is considered acceptable, and at times necessary, to get at ‘the truth’.”

I acknowledge of course that Hodgson’s study is two decades old, and that it is specific to France. Inquisitorial judicial systems are widely varied, and the French system itself has undergone significant reforms. So, I’m not saying that Hodgson’s study is necessarily representative of how all inquisitorial systems operate or even of how the French system operates today. But the point is that judicial supervision of the pre-trial investigation is not in itself a guarantee of justice. Both the inquisitorial and the adversarial system allow opportunities for oppression and miscarriage of justice.


I would also question whether Lomax is right in his assertion that inquisitorial systems tend to have lower rates of imprisonment. According to the Council of Europe, on 31 January 2020 the English and Welsh prison population was 138.8 per 100,000, only slightly ahead of the European average of 124.0.

Numerous European countries with civil law systems had higher rates of imprisonment, including Poland, the Czech Republic, the Slovak Republic, Estonia, Latvia and Lithuania. Conversely, the Republic of Ireland, which has an adversarial system based on the English model, had a rate of imprisonment of only 81.6, significantly below the European average.

In my view, Lomax doesn’t adequately justify his claim that there is a direct link between the adversarial system and higher rates of imprisonment. There are numerous other factors that we would expect to affect the imprisonment rate, including sentencing policy, judicial attitudes, crime rates and social inequality. Lomax doesn’t attempt to control for these factors. There is no doubt that we imprison far too many people in England and Wales and many factors are to blame for this. But I am unconvinced that switching to an inquisitorial system would bring those numbers down.

Is cross-examination beneficial?

Turning to the question of cross-examination, one of the distinctive features of the English adversarial system is the importance placed on cross-examination of witnesses. The traditional rule, in both criminal and civil cases, was that a party wishing to rely on the evidence of a witness had to call them to give evidence at trial. Hearsay was inadmissible except in very limited cases. And an advocate cross-examining a witness had to “put their case” to the witness. If the advocate failed to challenge the witness’s evidence in cross-examination, they would not be able to ask the judge or jury to disbelieve that evidence in their closing speech.

To some extent, English law has departed from the traditional position. Hearsay is now generally admissible in civil cases. And even in criminal cases, there have been changes in recent years, such as the curtailing of cross-examination in some cases for vulnerable witnesses and the use of Achieving Best Evidence (ABE) interviews. But it’s still the case in both criminal and civil cases that oral evidence and cross-examination are considered to be of great importance to the English system of justice. Cross-examination is one of the central skills in which English barristers are trained.

There are, however, several reasons to be sceptical about the value of cross-examination in getting at the truth. The first is that cross-examination technique often relies on catching the witness in an inconsistency. It relies on the assumption that if a witness contradicts him/herself, they must be lying. But we know from decades of psychological research that that assumption is false. Human autobiographical memory is highly fallible. We have a very poor memory for temporal information such as dates, duration and sequences, for proper names and for the exact words used in a conversation. And people can experience hypermnesia, remembering more over time, so a witness’s earlier account is not necessarily more accurate than their later account.

We also know all these problems are exacerbated in people with mental health problems. Depression and post-traumatic stress disorder can cause over-general memory, which make it more difficult to remember specific events in one’s past. The second is that the process of giving oral evidence may induce judges and juries to rely too much on a witness’s demeanour: whether they look and sound credible when giving evidence.

Such assumptions are unreliable because many factors may affect a person’s demeanour in court, such as cultural background, trauma and neurodivergence. In the past, appellate courts referred to the advantage that the trial judge gained from seeing and hearing the witness, but today there is increasing judicial recognition that demeanour is an unreliable guide to credibility.

The third is that the cross-examination process relies heavily on the experience and skill of the advocate. A seasoned barrister who has cross-examined hundreds of witnesses will generally do a better job than a pupil barrister doing his/her first trial.

To an extent, it also depends on the witness. An expert witness who’s been cross-examined hundreds of times will generally fare better than a nervous witness who’s in court for the first time. In short, how well a witness performs under cross examination is not necessarily a reliable guide to whether they are telling the truth.

A particularly serious problem in this regard has been the proliferation of unrepresented litigants, following the swingeing cuts to legal aid made by the Legal Aid, Sentencing and Punishment of Offenders Act 2012. A litigant in person cannot be expected to cross-examine effectively and is therefore at a huge disadvantage.

And in some cases, this creates an even bigger problem. It is obviously inappropriate that a person accused of sexual violence, for instance, should cross-examine their victim in person. But in the family courts, many people accused of sexual violence are now unrepresented. This sometimes forces the judge to descend into the arena by questioning the witness themselves, which can compromise the fairness of the proceedings.

You might think the solution is simple: just expand legal aid and fund it properly so everyone who needs to be represented is represented. And I agree that we should do that. But it isn’t a complete answer. It will still be the case that some counsel are better at cross-examination than others and some witnesses withstand it better than others, for reasons unrelated to the truth or falsehood of the evidence. On the other hand, this doesn’t necessarily mean the inquisitorial system would be better. As we have seen, that system suffers from its own problems. And it doesn’t escape the fundamental problem, which is that decision-makers are simply bad at assessing credibility.

As Hilary Evans Cameron states, “when it comes to assessing credibility, police officers, prosecutors and judges, as well as lay people, have ‘hit rates just above the level of chance’.” This problem will persist whether we have an adversarial system or an inquisitorial one. ■

Professor Leslie Thomas KC is a lecturer at Gresham College in central London 
Next week: The benefits and limitations of restorative justice

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