Reasonable Grounds to Believe

Reasonable Grounds to Believe

An extract from a presentation by Judge Malcolm Simmons to member of the Senior Judiciary in Male, Maldives 2017

Judge Simmons with the AG of the Maldives

In order to prevent police and investigation authorities exercising their powers in an arbitrary manner, certain safeguards are introduced in the Act.

Sections 26 (a), 29 (d), 30 (b), 35 (d) and (e), 36 (f), 38 (a), 40 (c), 55 (a), 56 (a) introduce the concept of “reasonable grounds to believe”.

For example, under Section 40 (c) police may arrest an accused without a warrant where they have reasonable grounds to believe the accused committed an offence, etc.

The requirement of ‘reasonable grounds to believe’ exists in various jurisdictions including England & Wales.

“The power possessed by constables to arrest without warrant … provided always that they have reasonable grounds for their suspicion is a valuable protection to the community; but the power may easily be abused and become a danger to the community instead of a protection. The protection of the public is safeguarded by the requirement, alike of the common law and, so far as I know, of all statutes, that the constable shall before arresting satisfy himself that there do in fact exist reasonable grounds for suspicion of guilt.”[1]

Given the importance of “reasonable suspicion” in the context of police powers of arrest, it is no great surprise that the courts have often been called upon to determine the lawfulness of an arrest by reference to this essential requirement. The result has been a fairly substantial body of case law at the appeal court level. Chief amongst the authorities is the House of Lords decision in O’Hara v. Chief Constable of the RUC [1997] AC 286 (see further below).

The decision in Castorina v. Chief Constable of Surrey (1988) LG Rev R 241 is a further authority that has been much cited in subsequent cases on account of the dictum of Woolf LJ. In that case, Woolf LJ commented that whether or not an arrest was lawful depended upon the answers to three connected questions. Those questions were:

  1. Did the arresting officer suspect that the person who was arrested was guilty of the offence? The answer to this question depends entirely on the findings of fact as to the officer’s state of mind. This is a subjective element of the test.
  2. Assuming the officer had the necessary suspicion, was there reasonable cause for suspicion? This is a purely objective requirement to be determined by the Judge on the facts.
  3. If the answer to the two previous questions is in the affirmative, then the officer has a discretion which entitles him to make an arrest. However, in exercising that discretion the officer must act reasonably.[2]

Part 1: The Police Officers State of Mind

The starting point is the arresting officer’s state of mind at the time of the arrest. The question to consider at this stage is whether or not that officer had the necessary suspicion that the person he intends to arrest has committed an offence.

In the case of Hussein v. Chong Fook Kam [1970] AC 942, Lord Devlin defined “suspicion” in the following terms:

“Suspicion in its ordinary meaning is a state of conjecture or surmise where proof is lacking: ‘I suspect but I cannot prove’. Suspicion arises at or near the starting point of an investigation of which the obtaining of prima facie proof is the end.”

Plainly the threshold for the foundation of a suspicion is a low one. Suspecting a person of having committed a criminal offence falls a long way short of having demonstrable proof that this is the case. Furthermore, it is a test that has a subjective foundation. What matters is what the arresting officer thought, not what the reasonable person would have thought in the particular circumstances.

Part 2: Assuming the officer had the necessary suspicion, was there reasonable cause for suspicion?

Once a court is satisfied that an officer did have the necessary suspicion (a question of fact), it is then required to determine the reasonableness of that suspicion. If it cannot be shown that there were reasonable grounds for a suspicion that was genuinely held, the arrest will have been unlawful.

Part 3: Where there are reasonable grounds for the suspicion, the arrest will be lawful unless it can be shown that the officer’s exercise of the power was unreasonable.

A reasoning or decision would be unreasonable (or irrational) if it is so unreasonable that no reasonable person acting reasonably could have made it.[3]

Three recent appeals heard by the Court of Appeal have shed further light on what may constitute “reasonable suspicion” in the context of arrest. Each related to Part 2 of the test – in other words, each centered on whether an officer’s suspicion that an arrested person had committed an offence was reasonable in the circumstances of the case.

Armstrong v. Chief Constable of West Yorkshire Police [2008] EWCA Civ 1582

The appeal in the present case was brought by the Chief Constable. It was against the decision of a Recorder, sitting in the Leeds county court, who had ruled that there had been no reasonable grounds for the arrest of the respondent on suspicion of having raped a young woman. The victim had provided a statement to the police that contained a description of the rapist as follows:

“A white male. 19 or under. Over six-foot. Slim. Light brown hair which was cut short under a dark baseball cap with a white symbol on it. Navy blue hooded sweatshirt with big white symbols on the front. Hood down. Clean shaven. Big starring eyes. Dark jeans and a Leeds accent.”

The description struck a chord with the rape victim liaison officer involved with the case. She informed one of the investigating officers that it matched the respondent who was known to both her and her 20 year-old daughter. The officer leading the investigation decided, with the senior investigating officer’s approval, to arrest the respondent. He did so because he was of the opinion that there were seven or eight respects in which the respondent possibly matched the rapist. During the course of the appeal, they were set out by Hallett LJ as follows:

“He frequented the clubs of Leeds City Centre; he might have been a doorman, and therefore known to other doormen; he had two previous convictions for theft, and he might have described himself as a thief; he lived near the attack; he fitted the offender’s general description; he had worn recently clothing of the kind described by the victim; and he was known as Daniel and not Dan or Danny” (at [5]).

The significance of the previous convictions for theft was that after the rape, the attacker had stolen items from the victim’s handbag and had described himself to her as a thief. Also, when she had asked him what she should call him he had replied “Daniel” and had objected when she tried to shorten it to “Dan” or “Danny”.

The Recorder was not satisfied by the seven or eight points referred to above. In the words of Hallett LJ, “he picked them off one by one, comparing them with what the officers knew about the respondent by the time of his arrest”. Thus, for example, the Recorder was of the view that the fact that the respondent frequented the centre of Leeds did not distinguish him from a large number of young people. Having analyzed the various points, the Recorder was of the view that they could be reduced to two: “the respondent was called Daniel, and lived within walking distance of the attack” (at [9]). In his judgment, these two factors were insufficient to provide reasonable grounds for making an arrest.

In giving judgment in favour of the respondent, the Recorder had regard to the authorities, including the decision in O’Hara v. Chief Constable of the RUC [1997] AC 286. That case is important in that it makes it clear that the test to be applied is the state of mind of the arresting officer at the material time (subjective) and whether or not his or her suspicions were reasonable in the circumstances (objective). Their Lordships also rejected the proposition that an order to arrest a person issued by a senior officer was sufficient in itself to form reasonable grounds for suspicion in the mind of the arresting officer. In the Recorder’s opinion, however, O’Hara was authority for the following proposition:

“… providing on the facts of the case a reasonable investigation has been undertaken, reasonable suspicion will be demonstrated, but it follows from that that [a reasonable] investigation is required.”

In the Court of Appeal’s judgment in Armstrong, the Recorder had erred in thinking that this is what O’Hara decided. Thus although the Court of Appeal was prepared to accept that the “thoroughness of an investigation may well be relevant as part of the whole surrounding circumstances”, and that on some occasions, those circumstances may make it “incumbent upon an officer to make further enquiries before ‘suspicion could properly crystallize’”, nevertheless it was:

“… important to remember … that an arrest may be effected very early on in an investigation, and it is nonetheless lawful for that. It will not always be possible or indeed desirable to carry out further inquiries before making an arrest” (per Hallet LJ at [14]).

In the judgment of the Court of Appeal, the Recorder had failed to bear the authorities sufficiently in mind in reaching his decision. Accordingly, he had “pitched the level of the threshold for suspicion too high” (at [15]). What Hallett LJ referred to as “his natural sympathy for an innocent man” had “unduly coloured what was meant to be an objective consideration of whether or not the officers had reasonable grounds to suspect the respondent”. In dismissing most of the seven or eight points against the respondent, the Recorder had “fallen into the trap of over-compartmentalizing the various pieces of information”. Instead, he ought to have borne in mind their cumulative effect. In the judgment of Arden LJ, who had “not found this an easy case”, the Recorder’s “over-compartmentalized approach to the individual items” amounted to a misdirection in law. Accordingly, the Court of Appeal unanimously agreed that the Chief Constable’s appeal be allowed.

Alford v. Chief Constable of Cambridgeshire [2009] EWCA Civ 100

Here, the appellant was a police constable who had been involved in a car pursuit which had ended with the pursued vehicle crashing, killing the passenger in the vehicle. An investigation carried out by another police force under the management of the Independent Police Complaints Commission had led to the appellant being arrested on suspicion of causing death by dangerous driving. Although he was later charged with that offence, the prosecution was ultimately discontinued. The appellant subsequently brought a claim against the Chief Constable for false imprisonment and malicious prosecution. That claim was dismissed at the conclusion of a four day trial. An appeal against that decision raised several issues. For present purposes it was the first of these, whether there were reasonable grounds to suspect that the appellant had committed the offence, which is important.

In addressing this issue, the Court of Appeal had regard to the judgment of Sir Anthony Clarke MR in Commissioner of Police of the Metropolis v. Raissi [2008] EWCA Civ 1237, where his Lordship had quoted the three questions posed by Lord Woolf in Castorina. Richards LJ noted that on the basis of the authorities in Lister v. Perryman (1870) LR 4 HL 521 and Dallison v. Caffrey [1965] 1 QB 348, it was “settled that the question whether the established facts disclose reasonable grounds for an arrest or a prosecution is a question of law to be decided by the Judge…” (at [32]). Continuing on the same theme, Richards LJ observed:

“A decision on the existence of reasonable grounds for arrest or prosecution will also involve an evaluation of the facts and, in many cases, a weighing of different factors… In my view the question is one to which an appellate court has to reach a conclusion of its own, rather than limiting itself to deciding, for example, whether the trial Judge’s conclusion was plainly wrong. If, however, the trial Judge has approached the task correctly, it will generally be appropriate to place weight on his assessment, given his proximity to the evidence and his better overall “feel” for the case: and I would expect an appellate court to be slow in practice to interfere with the trial Judge’s conclusion” (at [33]).

Applying this approach to the facts of the appeal in Alford, the Court of Appeal was of the view that whether or not the arresting officer had reasonable grounds for his suspicion resulting in the arrest of the appellant was to “be determined as an objective question on the basis of the matters known to him at the time”. It was therefore irrelevant that at the time that the arrest was made, there was in existence an expert evidence report which contradicted an earlier expert report by taking the view that the appellant had not caused death by dangerous driving. It was irrelevant because the arresting officer did not know of its existence at the material time, and there was no evidence to suggest that it had been deliberately withheld from him by other officers. The arresting officer was a pursuit trained advanced driver. He had also had the opportunity to watch a video recording of the fatal pursuit, and to read the original expert report (the Price report) that had been critical of the appellant, prior to making the arrest. On the basis of these factors, Richards LJ concluded:

“In my judgment the matters known to Sergeant Johnson [the arresting officer] did provide reasonable grounds for his suspicion that the appellant had committed the offence. He was able to, and did, form his own assessment of the quality of the appellant’s driving from his study of the video and the route. He had sufficient expert knowledge for that purpose … Moreover, the Price report provided expert support for Sergeant Johnson’s assessment. Bearing in mind the relatively low threshold for the existence of reasonable grounds, there can in my view be no doubt that reasonable grounds existed here for the suspicion on which the appellant’s arrest was based” (at [36]).

Buckley and others v. Chief Officer of the Thames Valley Police [2009] EWCA Civ 356

The claimants, three brothers, had been arrested on suspicion of being involved in a hit and run incident whereby a van had been driven at speed through a set of red lights and had knocked down and killed a pedestrian. A witness to the incident had reported that three young men had run off from the van following the collision. A check of the van’s registration plate revealed that it had no registered keeper. It also revealed that it had been stopped by the police some 17 days previously, and that it had been established that the driver was a man named Buckley, or his partner, and that they lived at an address nearby the scene of the incident. The radio traffic relating to the identification of the van had been heard by an officer who rang the control room to say that there were a number of youths in a family called “Buckley” who would be at the right age to fit the description provided by the witness. Police officers were therefore dispatched to their home address as well as to the home address of the driver who had previously been in possession of the van. The three claimants were all arrested and held in police custody until the following day, by which time further inquiries had eliminated them from the investigation. They subsequently sued the Chief Constable for wrongful arrest.

In determining the case, the question for the trial Judge had been, in the words of Hughes LJ in the Court of Appeal, “not whether they were guilty, nor whether there was a prima facie case of guilt against them”. Rather, “it was the quite separate question of whether there existed lawful grounds for their arrest” (at [6]).

The claim had failed because the trial Judge ruled that the arresting officer did have reasonable grounds to suspect that the claimants were responsible for the hit and run. In reaching this conclusion, he had accepted that the arresting officer had in mind at the relevant time various factors that gave rise to the necessary reasonable suspicion. On appeal, counsel for the claimants advanced various arguments as to why the trial Judge’s decision had been wrong. Thus, for example, it was submitted that the trial Judge had failed to follow the Court of Appeal’s earlier decision in Commissioner of Police of the Metropolis v. Raissi [2008] EWCA Civ 1237, where it was held that the fact that an arrested person was the brother of a suspected terrorist and was on close terms with him was insufficient by itself to amount to reasonable suspicion. In Buckley, however, Hughes LJ distinguished Raissi on the basis that a family relationship was but one of the factors that had led to the arrest of the claimants. His Lordship also doubted counsel’s interpretation of the ratio in O’Hara that, it was contended, was that an arresting officer was not simply able to rely on what he had been told by other more senior officers. In the words of Hughes LJ:

“There is not the slightest doubt, and O’Hara makes it crystal clear, that an arresting officer may rely on what he had been told by others who may be civilian informants, reliable or unreliable, or other officers, providing that the information thus assembled provides reasonable grounds for suspicion. Indeed if it were otherwise cooperation between officers and the management of any inquiry of any size would be impossible” (at [9]).

There was also criticism by counsel of the arresting officer’s failure to investigate the claimants’ alibi, ie, that they had been elsewhere at the time of the incident. This line of argument was also rejected by Hughes LJ. Thus he observed:

“… to criticize the officer for not investigating a possible alibi is to confuse the progress of an inquiry and the business of the proof of guilt with the existence of a reasonable suspicion at a stage which will necessarily be the outset of the inquiry. It has been said time and again in this court and indeed in the House of Lords that the necessity to demonstrate reasonable grounds for suspicion does not import any obligation upon the police constable to investigate possible defences. Of course if a suspect immediately produces a verified alibi that may well dispel the suspicion which reasonably existed or the reasonable grounds for it which previously existed. That, however, is a different proposition” (at [10]).

Hughes LJ concluded his judgment with several observations that reach beyond the confines of the present appeal. Thus he remarked:

“The threshold for establishing reasonable grounds for suspicion is, as the cases make clear and as is necessary, a low one. Importantly, the correct approach to judgment upon the lawfulness of arrest is not to separate out each of the … elements of the constable’s state of mind and ask individually of these whether that creates reasonable grounds for suspicion, it is to look at them cumulatively, as of course the arresting officer has to at the time” (at [16]).

In a far shorter judgment in Buckley, Pill LJ observed that the factors in the arresting officer’s mind at the time of the arrest were “cumulatively sufficient to establish that the officer’s grounds for suspecting that the claimants had committed the offence for which they were arrested were reasonable” (at [21]). Accordingly, the Court of Appeal was of the unanimous view that the arrests had been lawful and the claimants’ appeal was therefore dismissed.


“Reasonable suspicion” is an important safeguard in relation to police powers under the Act. It now exists to ensure that the power is not exercised in an arbitrary fashion. However, as each of the three appeals demonstrate, the threshold for establishing “reasonable suspicion” is necessarily a low one.

It would clearly be contrary to the public interest if police officers who were investigating the commission of a criminal offence were required to establish a prima facie case against a defendant before that person could be arrested. If such were the case, the law would have set the bar too high. However, given that an arrest involves the deprivation of a person’s liberty, it is important that the safeguards which are in place do prevent the unnecessary arrest of the innocent.

None of the claimants in the three appeals had appeared before a criminal court charged with the offence for which they had been arrested. They were thus innocent of the crimes being investigated. Were their arrests therefore unnecessary? Arguably this question can only really be answered with the benefit of hindsight. Since an arrest can be made at an early stage of an investigation it is only likely to become apparent at a later stage that a person need not have been arrested.

Although an arrest is an invasion of a person’s right to liberty, it is submitted that the arrest of the innocent is a price which inevitably has to be paid if it means that that those who are ultimately found guilty have been expeditiously taken into police custody before they can flee from justice or commit further offences.

[1] Per LJ Scott in Dumbell v. Roberts [1944] 1 All ER 326

[2] Lord Greene MR in Associated Provincial Picture Houses Ltd v. Wednesbury Corporation [1948] 1 KB 223

[3] Associated Provincial Picture Houses Ltd v Wednesbury Corporation (1948) 1 KB 223