Constructive res judicata bars later suits where an available constitutional plea was omitted in an earlier writ petition.

Constructive res judicata bars a later suit where a constitutional plea was available in an earlier contested writ petition but was not raised. The principle, grounded in finality of adjudication and avoidance of multiplicity, extends beyond section 11 CPC and applies to writ proceedings under Article 226. Because the authority challenge to the dismissal order could and ought to have been taken in the earlier proceeding, the omitted plea could not be reopened in the subsequent suit on the same subject matter.

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Issues: Whether the respondent's suit challenging the dismissal order was barred by constructive res judicata because the constitutional plea available in the earlier writ petition had not been raised there.

Analysis: The rule of res judicata is founded on finality of adjudication and the prevention of multiplicity of litigation. Its constructive form extends to matters which could and ought to have been raised in the earlier proceeding. Though section 11 of the Code of Civil Procedure, 1908 speaks in terms of suits, the same principle has been applied to writ proceedings under Article 226 of the Constitution of India. The earlier writ petition had been contested and had failed, and the plea that the Deputy Inspector General of Police lacked authority under Article 311(1) of the Constitution of India was available to the respondent then but was omitted. That omission could not be cured by raising the plea in a later suit on the same subject matter.

Conclusion: The subsequent suit was barred by constructive res judicata, and the respondent was not entitled to reopen the omitted plea.

Ratio Decidendi: A plea available in an earlier contested writ petition, though not actually raised, cannot be raised in a later suit if it could and ought to have been taken earlier, because constructive res judicata applies to writ proceedings as well.

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