Bob runs a shop, and every week or so he catches a shoplifter and dutifully lays the information before his local magistrate court to prosecute them each time of thousands within the week.

One time a customer, Cassandra, has an awful time in Bob’s shop, and Bob spits on her while shouting all manner of abusive sexist invectives at her.

She writes to Bob complaining of his hateful conduct toward her the prior week, explaining how it upset and impacted her so, asking him for an explanation for his tirades and abuse, and insinuating that she may be weighing civil legal action against Bob for his sexist harassment.

Bob, embarrassed and apparently backed into quite the humiliated spot, apparently spends a couple of days trawling through all of the security footage that he has from the last 6 months trying to find something he might have of Cassandra committing a crime, and manages to find a clip of her running a red light at the junction outside his shop just before arriving one day 5 months ago, still leaving a whole month for the summary only offence to be laid at Magistrates’.

Bob writes back to Cassandra advising her that he has found footage of her running the red light on his camera systems back in May, and is looking into prosecuting her for it.

While one may wonder as to the supposable purpose of the “warning” letter, irrespective of the preliminary threat, can the apparently unsavoury ulterior motives of Bob in prosecuting the offence be used to cast doubt on the ultimate merits of his charges laid against Cassandra?

Is this an illustration of “malicious prosecution”? If not, then what is that?

2 Answers 2


To succeed in an action for malicious prosecution, a plaintiff must prove that the prosecution was: (1) initiated by the defendant; (2) terminated in favour of the plaintiff; (3) undertaken without reasonable and probable cause; and (4) motivated by malice or a primary purpose other than that of carrying the law into effect.

(Miazga v. Kvello Estate, 2009 SCC 51, para. 3)

This is essentially the same test as in England and Wales:

To ground a claim for malicious prosecution a plaintiff must prove (1) that the law was set in motion against him on a criminal charge; (2) that the prosecution was determined in his favour; (3) that it was without reasonable and proper cause, and (4) that it was malicious: Martin v. Watson [1996] 1 A.C. 74, 80.

(Gregory v. Portsmouth City Council, [2000] UKHL 3)

Unless all four elements are present, there is no malicious prosecution. This tort goes back to the time of Edward I and has been available against private prosecutors (Nelles v. Ontario, [1989] 2 S.C.R. 170).

In your hypothetical, Bob had reasonable and probable cause, which precludes a malicious prosecution claim. Further, the prosecution has not yet resolved in favour of Cassandra: if she is found guilty, this cannot be malicious prosecution.

For an example of a successful malicious prosecution claim, see Proulx v. Quebec (Attorney General), 2001 SCC 66, also described in a case summary in the Canadian Registry of Wrongful Convictions. There was no reasonable and probable cause, and a member of the investigation team was simultaneously a defendant in a defamation suit brought by the accused.

  • This answer addresses quite well the parenthetical but not the main question… Commented Oct 25, 2023 at 3:32
  • In other words I’m still left wondering does it have a bearing on the ultimate outcome/merit of the prosecution? Commented Oct 25, 2023 at 3:45
  • okay, well on the one hand I guess I would have hoped that it would be inherently clear that the parenthesised portion was a secondary corollary and not the primary question, while on the other, point taken. But in any case, what should I do now…? Would it offend you if I now edited the question to better reflect the primary original intention? Commented Oct 25, 2023 at 4:26
  • 1
    +1. The answer would be the same in the United States.
    – bdb484
    Commented Oct 25, 2023 at 13:24
  • 2
    Yeah, his motivations generally have no legal effect on his capacity to prosecute the case.
    – bdb484
    Commented Oct 26, 2023 at 3:17

While this might not be malicious prosecution from the state side, Bobs actions might still backfire in his case vs Cassandra. That's because Bob has no reason to install CCTV in such a way that he can see the crossroads and the red light outside his shop. Data protection laws will generally disallow taking footage without a well-estabilshed reason, and catching people running on red ligths is none of his business and also does not help him in preventing shoplifting.

Additionally, CCTV footage - even for the inside of a shop, where such equipment is normally legal - may typically be stored for 1 to 3 days and must be deleted afterwards. Certainly not 6 months.

  • This seems to do nothing to answer the actual question. Also, there's no citation to any law, making it indistinguishable from a random guess.
    – bdb484
    Commented Oct 26, 2023 at 3:18

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