Definition
A common informer is a private person who, without holding public office or bearing any special legal duty, makes a practice of detecting violations of penal statutes and bringing accusations or prosecutions against offenders — motivated primarily or entirely by entitlement to a share of the resulting fine, penalty, or forfeiture rather than by civic obligation or personal injury. The common informer operated within a formally recognized legal mechanism: penal statutes enacted by legislatures often included a qui tam provision, which awarded a portion of the penalty to "any person who shall sue" for its enforcement. The common informer was the private party who supplied the information and triggered that process.
The term carries two layers of meaning that should be kept distinct:
(1) The procedural actor: the individual who files an action under a qui tam or penal statute and claims the informer's share of the recovery.
(2) The social type: a person who makes a habitual or commercial practice of ferreting out violations, cultivating this as a business or profession rather than acting from a specific grievance.
Both senses converge on the same figure, but legal sources emphasize the procedural role while historical commentary emphasizes the social character.
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Common Language
Modern common usage (Wiktionary): A person who gives evidence in a criminal trial solely for the purpose of receiving the penalty or forfeiture recovered from the defendant.
Historical common usage (Webster's 1913): [No distinct entry for this compound term; "informer" in general usage referred to one who informs against another, often carrying a connotation of treachery or self-interest.]
The ordinary word "informer" in common speech suggests a snitch or betrayer — someone supplying incriminating information about another person, often with dishonorable overtones. The legal term "common informer" is narrower and more technical: it refers specifically to the enforcement mechanism under penal statutes, not to a witness or police informant in the modern sense. A researcher who reads "informer" in a historical legal source should not assume it describes someone cooperating with police; it may instead describe a private plaintiff pursuing a financial share of a statutory penalty.
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Common Confusion
Common informer and qui tam relator are closely related but not identical in all contexts. A qui tam relator is the modern American term for a private party who brings suit on behalf of the government under a statute such as the False Claims Act and shares in any recovery. The common informer is the historical English antecedent of this figure, though the structural logic is the same. In English legal history, the common informer frequently acted without any governmental co-party at all, suing directly on the penal statute in his own name for his own share. Modern qui tam actions retain government involvement as a formal matter. Researchers should also not confuse the common informer with a government informant or confidential informant, which are police-cooperation concepts with no connection to penal statute enforcement shares.
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Why It Matters in Research
The common informer is a term anchored almost entirely in English legal history and early American statutory law. Researchers encountering it in primary sources face several navigational challenges.
First, the institutional context has largely disappeared in modern law. England effectively abolished the common informer mechanism for most purposes through the Common Informers Act 1951, substituting public enforcement. American federal law preserved a structural descendant in the False Claims Act's qui tam provisions, but the term "common informer" itself fell out of use. A researcher working in 19th-century American materials will encounter the term frequently; a researcher in 20th-century materials almost never will unless the source is historical in orientation.
Second, penal statutes that supported common informer actions were extraordinarily numerous in English and early American law. Customs duties, excise taxes, licensing requirements, and trade regulations all commonly included informer shares. This means the term appears across an enormous range of subject matter — tax, commercial regulation, labor law, licensing — and a researcher focused on any one of those fields may encounter the figure without recognizing it as a procedural mechanism rather than a substantive doctrine.
Third, the moral and reputational status of the common informer in historical sources is deeply hostile. Blackstone and his commentators treat the common informer with open contempt, and legislative history of reform statutes reflects this. Researchers should recognize that evaluative language in historical sources about informers is colored by this hostility and does not necessarily describe legal disability or procedural illegitimacy — the common informer was lawful, even if despised.
Fourth, the connection to modern qui tam doctrine is important for tracing doctrinal lineage. Courts and scholars writing about the False Claims Act frequently reach back to the common informer tradition to analyze the constitutional and structural foundations of private enforcement of public law. A researcher tracing qui tam doctrine backward will pass through this term.
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Historical Dictionary Support
The three source dictionaries agree on the essential structure of the definition: a private person, no official duty, detection of penal statute violations, prosecution or information, share of the forfeiture as motive. Burrill's entry is the most precise, specifying that the person makes "a business" of the practice and citing Blackstone's Commentaries (3 Bl. Com. 160) and Crabb's History of English Law — the two most important authorities on the subject. Black's two entries show some disorganization in the source scans, but the substantive content aligns with Burrill and Bouvier.
Bouvier's definition is the broadest, describing the common informer as simply "one who gives information of crimes, offences, or misdemeanors" without official requirement — which risks conflating the common informer with any private complainant. The narrowing element, present more clearly in Black's and Burrill's, is the financial motive tied to a share of the forfeiture under a penal statute. Researchers relying on Bouvier alone may over-read the definition.
None of the source dictionaries address the legislative abolition of the common informer mechanism or its survival in modified form in American qui tam doctrine, both of which post-date or lie outside the scope of the historical editions.
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Jurisdictional Note
The common informer as a formal legal mechanism was largely an English institution, and its American presence tracks the adoption of English-style penal statutes in the colonial and early national periods. States varied considerably in how broadly they permitted private informer actions and how informer shares were structured. By the late 19th century, most American jurisdictions had moved toward public enforcement of regulatory statutes. The federal False Claims Act (1863, substantially revised 1986) is the most significant modern survival of the underlying mechanism, but it operates under its own developed doctrine and is not typically described using the historical term.
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Encyclopedia Cross-Reference
Common Fund and Common Benefit Doctrines — Fee Awards from Litigation Proceeds (The Law Mind Remedies & Equity Encyclopedia): Provides relevant context for understanding private parties recovering shares of litigation proceeds, the structural logic underlying informer shares, and the relationship between private enforcement mechanisms and fee or recovery awards.
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