Civil P.C. (5 of 1908) , S.11— Kerala Buildings (Lease and Rent Control) Act (2 of 1965) , S.15— Res judicata - Bar to eviction under S. 15 of Rent Control Act - Question as to - Decided at earlier stage of eviction suit - Also allowed to become final - Cannot be reagitated at subsequent stage of suit. The principle of res judicata applies as between two stages in the same litigation so that if an issue has been decided at an earlier stage against a party it cannot be allowed to be reagitated by him at a subsequent stage in the same suit or proceeding. Thus, where the question whether S. 15 of the Act bars the eviction petition, was decided against the tenants by the appellate authority at the earlier stage of suit and it was allowed to become final, it is not open to the tenants to reagitate the same at the subsequent stage of the suit.