JUDGMENT : 1. The plaintiffs in the suit are the appellants. 2. The facts relevant for adjudication of the questions raised in the second appeal are the following: The plaintiffs are husband and wife. The plaint schedule property belongs to the plaintiffs absolutely and they are in possession of the same. The plaint schedule property forms part of a cluster of paddy fields (padasekharam) measuring approximately 360 acres and managed by a Committee. The first defendant in the suit is the Committee and the remaining defendants are its office bearers elected from time to time. Three motor pumps are installed at different places of the paddy fields by the Committee for draining out the water collected in the paddy fields and one of the said motor pumps is installed in the plaint schedule property which being one situated adjoining the river to which water is being drained out. It has been a practice to catch the fish by keeping fishing nets at the mouth of the motor pumps installed for draining out the water from the paddy fields. The case of the plaintiffs is that the fishery being their property, they have the exclusive right to catch the fish, notwithstanding the fact that the fishery is formed on account of the pumping activity undertaken by the Committee. It is also their case that both the plaintiffs as also the Committee were under the mistaken impression that the right to catch fish from the mouth of the motor pumps vests with the Committee and consequently, they have agreed to pay an yearly sum to the Committee to enable them to catch fish from their own property in terms of an agreement. According to the plaintiffs, the agreement entered into by them with the Committee being one vitiated by a common mistake is void. On the said case, the plaintiffs sought a declaration that they have the exclusive right to catch fish from the water that is drained out into their property on account of the pumping activity undertaken by the Committee. They have also claimed a decree of permanent prohibitory injunction restraining the defendants from interfering with their fishing activity and also a decree for return of the amounts paid to the Committee in terms of the agreement. 3. The defendants contested the suit. They have also claimed a decree of permanent prohibitory injunction restraining the defendants from interfering with their fishing activity and also a decree for return of the amounts paid to the Committee in terms of the agreement. 3. The defendants contested the suit. The stand taken by the defendants is that the owners of the paddy fields have a customary right over the fishery formed on account of the pumping activity and the plaintiffs cannot claim exclusive right over the same merely for the reason that the fishery is formed in their property. 4. The trial court found that the plaintiffs have the exclusive right over the fishery, though the fishery is formed on account of the pumping activity undertaken by the Committee and consequently, decreed the suit. The first defendant challenged the decision of the trial court in appeal. The appellate court though confirmed the finding of the trial court that the plaintiffs have absolute right over the fishery, reversed the decision of the trial court and dismissed the suit holding that the plaintiffs having entered into Ext.A3 agreement with the first defendant, are not entitled to the decree sought for in the suit. The plaintiffs, who are aggrieved by the decision of the appellate Court, have thus come up in the second appeal. 5. Heard the learned counsel for the appellants. 6. The learned counsel for the appellants contended that Ext.A3 agreement is one entered into by the parties under the mistaken belief that the first defendant has the exclusive right over the fishery. According to the learned counsel, insofar as it is found that the first defendant has no rights whatsoever over the fishery and the plaintiffs have the exclusive right over the same, the agreement is void under Section 20 of the Indian Contract Act, 1872. The submission of the learned counsel, in the circumstances, is that the appellate court ought not to have interfered with the decision of the trial court. 7. After hearing the learned counsel for the appellants, the following substantial question of law is framed for decision in the second appeal: “Is Ext. A3 agreement void under Section 20 of the Indian Contract Act, 1872 being one vitiated by a common mistake as to a matter of fact essential to the agreement?” 8. 7. After hearing the learned counsel for the appellants, the following substantial question of law is framed for decision in the second appeal: “Is Ext. A3 agreement void under Section 20 of the Indian Contract Act, 1872 being one vitiated by a common mistake as to a matter of fact essential to the agreement?” 8. Section 20 of the Indian Contract Act, 1872 provides that where both the parties to an agreement are under a mistake as to a matter of fact essential to the agreement, the agreement is void. No doubt, in order to attract the provision aforesaid, it must be a common mistake of both parties to the contract about the same vital fact and the mistake must also be as to the substance or essential and integral element of the contract. (See ITC v. George Joseph Fernandes (1989) 2 SCC 1 )). The classic case on the point is Cooper v. Phibbs ((1867) LR 2 HL 149). That was a case where an uncle told his nephew, not intending to misrepresent anything, but being in fact in error, that he was entitled to a fishery. The nephew, after the death of the uncle, believing the truth of what the uncle had told him, entered into an agreement with the daughters of the uncle to rent the fishery. It was turned out later that the fishery actually belonged to the nephew himself. As the daughters of the uncle and nephew all had assumed that the fishery belonged to the uncle, the nephew instituted the suit for a declaration that the fishery belongs to him and that the lease is not enforceable. In the said case, Lord Westbury applied the principle that if parties contract under a mutual mistake and misapprehension as to their relative and the respective rights, the result is that the agreement is liable to be set aside as having been proceeded upon a common mistake. Although it was held in some of the later English cases that the proposition laid down in Cooper v. Phibbs is too wide, it is seen that the principle therein has been consistently acted upon as an authority. Although it was held in some of the later English cases that the proposition laid down in Cooper v. Phibbs is too wide, it is seen that the principle therein has been consistently acted upon as an authority. It is seen that in Ram Rattan v. Municipal Committee [AIR 1939 Lah 511], in a case where a decree holder agreed to give up the costs, if the judgment debtor did not file appeal, it was held that the agreement is void as it was found that there was no right of appeal at all. It was clarified in the said case that it is because both parties believed that there was a right of appeal and had it been a case where the judgment debtor made a dishonest misrepresentation knowing fully well that he had no right of appeal, the contract would have been only voidable. 9. Coming to the facts of the case on hand, the recitals of Ext.A3 agreement indicates beyond doubt that both parties to the said document were maintaining the stand at the time of execution of the document that the fishery belongs absolutely to the first defendant. The striking coincidence is that the facts of the case on hand are almost identical to the facts in Cooper v. Phibbs. As the appellate Court found that the fishery belongs absolutely to the plaintiffs, according to me, it ought not to have interfered with the decision of the trial court. The substantial question of law formulated for decision in the second appeal, in the circumstances, is answered in favour of the appellants/plaintiffs. In the result, the second appeal is allowed, the decision of the appellate court is set aside and the decision of the trial court is restored.