Conspiracy — MCQs

All questions with answers and explanations

Read the full set here, or use the practice card above to test yourself one question at a time.

1. How many persons are required, at minimum, for the tort of conspiracy?

   • One person acting alone is sufficient
   • Two or more persons acting in combination (correct answer)
   • At least three persons
   • No minimum number is required

   Explanation. Conspiracy, by its very nature, requires a combination of two or more persons — a single individual cannot conspire alone.

2. What are the essentials of the tort of conspiracy?

   • Combination/agreement, an overt act pursuant to it, and actual damage to the plaintiff (correct answer)
   • Malice alone, without any need for damage
   • A written contract between the conspirators
   • Registration with a regulatory authority

   Explanation. The essentials are: a combination or agreement between two or more persons, an overt act done in pursuance of it, and actual damage suffered by the plaintiff — conspiracy is not actionable per se.

3. In a claim for conspiracy to injure by lawful means, what must the plaintiff prove about the defendants' purpose?

   • That the defendants used independently unlawful means
   • That the predominant purpose of the combination was to injure the plaintiff, not to advance the defendants' own legitimate interests (correct answer)
   • That the defendants acted with negligence
   • That the defendants had a written agreement to that effect

   Explanation. Lawful means conspiracy requires proof that the combination's predominant purpose was to injure the plaintiff, since each individual act involved is otherwise lawful.

4. In conspiracy by unlawful means, why is it unnecessary to prove the defendants' predominant purpose?

   • Because unlawful means conspiracy does not require any damage
   • Because the means used are already independently unlawful (e.g. a crime, tort, or breach of contract), which substitutes for the inquiry into purpose (correct answer)
   • Because only one defendant is required for this form
   • Because this form of the tort was abolished by statute

   Explanation. Since the means used are independently unlawful, it is enough that the combination used such means and damage resulted, regardless of whether the predominant purpose was to injure or to advance the defendants' own interests.

5. In Quinn v Leathem (1901), why were the union officials held liable for conspiracy?

   • Because they used physical violence against the plaintiff
   • Because their combination's predominant purpose was to injure Leathem's trade by coercing him over his employment practices, not to advance any legitimate interest of their own (correct answer)
   • Because they breached a written contract with Leathem
   • Because criminal charges had already been filed against them

   Explanation. The House of Lords found the union officials' predominant purpose was to injure Leathem's business through coercion, not to further any genuine trade interest of their own, making the lawful-means combination actionable.

6. What explains the different results in Quinn v Leathem and Mogul Steamship Co v McGregor, Gow & Co (1892)?

   • Mogul Steamship involved criminal conspiracy, while Quinn v Leathem was purely civil
   • In Mogul Steamship, the combination's predominant purpose was to advance the defendants' own legitimate trade interests, not merely to injure a rival, so no liability arose (correct answer)
   • Mogul Steamship involved a written agreement while Quinn v Leathem did not
   • Quinn v Leathem was decided by a lower court with no binding authority

   Explanation. In Mogul Steamship, the shipowners' combination was aimed at protecting their own trade through lawful competition, not simply injuring a rival. The object was lawful and no unlawful means were used, so the loss was damnum sine injuria. The difference lies in the predominant purpose.

7. What is the key distinction between civil (tortious) conspiracy and criminal conspiracy?

   • Civil conspiracy requires actual damage and is not complete on agreement alone; criminal conspiracy is complete the moment the unlawful agreement is made, without needing proof of damage (correct answer)
   • Civil conspiracy requires more than two persons; criminal conspiracy requires only one
   • Criminal conspiracy is a defence to civil conspiracy
   • There is no legal distinction between the two

   Explanation. Civil conspiracy is not actionable per se — it requires an overt act and actual damage. Criminal conspiracy is complete upon the unlawful agreement itself, with no requirement of damage.

8. Why is conspiracy described as not being 'actionable per se'?

   • Because mere proof of a combination and injurious purpose is insufficient — the plaintiff must additionally prove actual damage resulted (correct answer)
   • Because conspiracy can only be tried in criminal courts
   • Because it requires proof of malice in every case, unlike other torts
   • Because only government bodies can sue for conspiracy

   Explanation. Unlike many torts actionable on mere infringement of a right, conspiracy requires the plaintiff to go further and prove that real, actual damage resulted from the conspiracy.

9. Several grocers agree to pressure their common supplier into refusing to sell to a new competing retailer, purely to drive him out of business rather than for their own trade advantage. If the supplier complies and the retailer suffers real loss, this is best classified as

   • No tort at all, since refusing to supply a customer is always lawful
   • Conspiracy to injure by lawful means, since each individual act is lawful but the predominant purpose of the combination was to injure the retailer (correct answer)
   • Defamation, since the grocers spoke ill of the retailer
   • Battery, since physical pressure was applied to the supplier

   Explanation. Each act (a supplier declining to sell to one customer) is individually lawful, but the combination's predominant purpose was to injure the retailer rather than advance the grocers' own interests — this is lawful-means conspiracy.

10. If the same grocers had instead induced the supplier to breach an existing supply contract with the retailer, what changes about the plaintiff's case?

    • The claim would fail entirely, since inducing breach of contract is a defence
    • It becomes conspiracy by unlawful means, since inducing breach of contract is independently unlawful, and the plaintiff need not prove the grocers' predominant purpose was to injure (correct answer)
    • The claim could only be brought in criminal court
    • Nothing changes; the analysis remains identical

    Explanation. Inducing breach of contract is independently unlawful, so this becomes unlawful-means conspiracy — the retailer need not prove the grocers' predominant purpose was to injure him, only that unlawful means caused damage.