Judgment :- 1. The question raised in this Original Petition (filed under Art.227 of the Constitution of India) is whether the petitioner is debarred from taking up the plea that be is a kudikidappukaran. The ancillary question is whether such a question "arises" for decision in the proceedings initiated by a landlord against the petitioner. The District Court, while disposing of a revision petition filed under S.20 of the Buildings (Lease and Rent Control) Act, 1965 (for short 'the Act') found that the tenant is estopped from taking up such a plea. 2. The said finding is based on a previous rent control proceeding between the same landlord and tenant, in which the tenant did not raise the plea of kudikidappu. In 1975 the same landlord filed an application under S.11 of the Act against the same tenant as RCP. No. 73/75. In the objections filed by the tenant he took up several contentions but he did not advance a plea that he is a kudikidappukaran or that he has kudikidappu right. The landlord, for other reasons, did not pursue that petition. It was thus got dismissed. In 1983, the landlord filed the present rent control petition for eviction of the tenant on the grounds of arrears of rent and bona fide need for occupation. The tenant raised different contentions in resistance of the landlord's action and one of the contentions is that he is a kudikidappukaran of the building. During pendency of the present rent control proceedings, the landlord filed two interlocutory applications, one for a direction to the tenant under S.12 of the Act to deposit the admitted arrears of rent and the other for issuance of a commission. The former interlocutory application was dismissed on the ground that the objection filed by the tenant does not reveal that there is an admission regarding arrears of rent. It was also observed that there is no estoppel against the tenant as far as the claim of kudikidappu is concerned. But while allowing the other interlocutory application, the Rent Control Court expressed the view 'that since the tenant omitted to raise the plea of kudikidappu in the earlier rent control proceeding, it is impermissible for him to raise such a plea now. Both the said orders were challenged in appeal, at the instance of both the landlord and the tenant. But while allowing the other interlocutory application, the Rent Control Court expressed the view 'that since the tenant omitted to raise the plea of kudikidappu in the earlier rent control proceeding, it is impermissible for him to raise such a plea now. Both the said orders were challenged in appeal, at the instance of both the landlord and the tenant. Appellate Authority took the view that the tenant is not barred by res judicata to raise the claim of kudikidappu, though the point of estoppel as such was not considered. At the same time, the Appellate Authority directed the Rent Control Court to take up the application for issuance of commission only after receipt of a finding from the Land Tribunal on a reference under S.125(3) of the Kerala Land Reforms Act (Land Reforms Act, for short). The District Court, in revision, set aside the judgment of the Appellate Authority on the finding that "since the tenant failed to put forward the plea of kudikidappu in the earlier rent control proceedings, he could not validly put forward the said contention in the subsequent proceeding; the said contention now put forward is hit by rule of estoppel". This original petition is in challenge of the said order of the District Court. 3. Counsel for the petitioner did not dispute the factual position that the tenant had not taken up the plea or contention that be has kudikidappu right when he filed objections in the earlier rent control proceedings. When be raised the contention in the present proceedings, is the Rent Control Court bound to refer that question to the Land Tribunal as per S.125(3) of the Land Reforms Act? A larger Full Bench of this Court has held in Kesava Bhat v. Subraya Bhat (1979 KLT. 766) that it is only if the question "arises" under S.125(3) of the Land Reforms Act that the obligation to make the reference also arises. It was held in that decision that "we do not think it can be the intention of the legislature to make the reference to the Land Tribunal dependent upon a plea in the written statement which has got no relation to the claim made in the plaint and which would not having regard to the frame of the plaint or other legal obstacles in raising the defence, call for any adjudication at all" (emphasis supplied). Bar of the plea by res judicata is one of the legal obstacles. There can be other obstacles such as rule of estoppel and doctrine of lis pendens which may preclude a party from raising or advancing certain pleas. Hence the question which calls for consideration is whether the omission to raise a plea of kudikidappu in earlier proceedings would operate as a bar of estoppel in a subsequent proceeding. 4. Rule of estoppel is a rule of equity. That rule has gained new dimensions in recent years. (T. M. Co. v.H. I. Trust Ltd., AIR. 1972 SC. 1311). The omission to raise a plea regarding a right of the party concerned at the appropriate stage, if such omission has been consciously made, would amount to waiver of that right and hence the rule of estoppel sets in. The foundation of the rule is the equitable doctrine that it would be unjust if a person has induced another to believe a certain thing, and such person takes a contrary stand subsequently to the detriment of the interest of the other person. Though estoppel is a rule of evidence, as well, it may have the effect of creating substantive rights as against the person estopped (vide Mercantile Bank v. Central Bank, AIR. 1938 PC. 52). A Division Bench of the Punjab High Court has held that "the failure of a party to object when be bad a right to do so before the trial court constitutes a waiver of the right to object and precludes him from exercising the said right in the appellate court; such waiver or estoppel may arise from mere silence or inaction or from inconsistent conduct or statements or from admission or concession or consent..." (Inder Singh v. Deputy Commissioner, AIR. 1957 Punjab 60). This appears to be an extreme view, but even therein the principle which is given thrust to is the rule of estoppel. In a rent control proceeding under the provisions of Madras Buildings (Lease and Rent Control) Act, 1946, a tenant raised the plea that the premises did not fall within the definition of building under the said Act. When the landlord subsequently filed a civil suit for eviction the tenant raised the contention that eviction order can be obtained only by resort to the said Act of 1946. When the landlord subsequently filed a civil suit for eviction the tenant raised the contention that eviction order can be obtained only by resort to the said Act of 1946. A Division Bench of the Andhra Pradesh High Court in A. N. Shah v. Annapurnamma (AIR. 1959 A. P. 90) rejected the tenant's plea on the strength of rule of estoppel. The same principle can also be applied in a case where the tenant did not raise a relevant plea by which omission, the rent control court in the earlier proceedings did not have occasion to doubt about its own jurisdiction to entertain the petition filed by the landlord. The said decision thus offers good support in this case. S.2(6) of the Act defines the word "tenant". It is pertinent to note that a kudikidappukaran is exempted from the ambit of the said definition by virtue of the following specific words used therein: "but does not include a kudikidappukaran". The person against whom a landlord files an application under the Act must be a tenant as defined in the Act. If be is not a tenant, the application is not maintainable and the Rent Control Court has no jurisdiction to deal with such application. So when a landlord files an application before the Rent Control Court against any person describing him as a tenant, it is for that person to raise the plea that he is not a tenant as defined in the Act, but is only a kudikidappukaran. If such person does not raise such a plea, be thereby submits himself to the jurisdiction of the Rent Control Court by impliedly admitting his status as a tenant. He cannot, in a subsequent proceeding raise a plea that he is not a tenant, but is only a kudikidappukaran, because of the rule of estoppel. 5. In this case the petitioner is precluded from contending that he is a kudikidappukaran in view of his conscious omission to raise such a plea in the earlier rent control proceeding. Hence the question does not "arise" and therefore, there is no obligation to make a reference under S.125(3) of the Land Reforms Act. The order of the District Judge, therefore, does not require any interference. This original petition is accordingly dismissed in limine.