Judgment :- The judgement-debtor who is the petitioner in this revision is aggrieved against the order passed in E.P. 98 of 1984 in O.S. 66 of 1981 on the file of the Sub Court, Nagarcoil, in which execution was ordered after rejecting all his objections. 2. O.S. 86 of 1981 is an action laid for recovery of money on a promissory note and also for recovery of money on a mortgage. The suit came to be decreed on 5-3-1983. It is true that the decree dated 5-3-1983 does not conform to the form prescribed in the C.P.C. Nonetheless, a final decree application was presented in I.A. 547 of 1984. Ultimately, a final decree came to be passed on 27-10-1984. So far as the final decree is concerned, it is common ground that, it conforms to the form provided under the Civil P.C. On the strength of the final decree, the respondent decree-holder levied execution and was bringing the hypotheca to sale. It is at that stage, several objections were raised by the present petitioner-judgement-debtor. As already stated all the objections were overruled by the Court below. 3. Learned counsel for the petitioner would submit that the decree dated 5-3-1983, as it reads, will not be a preliminary decree as visualised under the Civil P.C., on the other hand, it is a mere money decree; while so, even the final decree passed on the strength of the said defective decree dated 5-3-1983 will not be a valid one. It is thus, according to the learned counsel for the petitioner, he can challenge the very executability of the final decree itself. The other point urged by the learned counsel for the judgement-debtor petitioner is that the preliminary decree provided only interest at 6 per cent per annum, and, therefore, the decree-holder is not entitled to claim interest at 12 per cent per annum, as he had done in his execution petition. 4. As regards the second point, I find that contention is well founded. Though in law, the mortgagee decree-holder is entitled to claim interest at the contract rate till the date of redemption is fixed, yet if the Court has fixed the rate of 6 per cent and if the decree-holder has not challenged that decree, naturally he is bound by the decree passed on 5-3-1983, fixing interest at 6 per cent per annum. Quite rightly, the learned counsel for the respondent fairly conceded that he cannot claim more than six per cent. Accordingly, it is made clear that the respondent is entitled to claim interest only at 6 per cent per annum from 5-3-1983 till the date of realisation. I must immediately point out that this point was not at all considered by the learned subordinate Judge of Nagarcoil. Then his order has to be interfered with at least to this extent. 5. I am unable to find any merit in the other contention advanced by the learned counsel for the petitioner. A reference to the preliminary decree discloses that the suit itself was laid both on a promissory note and on a mortgage and that court-fee had been paid both under Ss.22 and 33 of the Court-fees Act respectively. This will show that the suit is laid also on a mortgage. The operative part of the decree fixes liability of the judgement-debtor via-a vis the decree-holder in respect of the claim made on a promissory note and also in respect of the claim made on a mortgage. In other words, the decree-holder occupies a dual position. This obviously has been lost sight of by the person, who drafted the decree and also the learned Judge who signed the decree. In my view, that is a mere procedural irregularity which can be cured by the Court at any stage. In this case, fortunately for the decree-holder that irregularity had been cured by his taking out an application in I. A. 547 of 1984, for passing a final decree. In the final decree proceedings, the present objection that the preliminary decree is not in conformity with the form prescribed under the Civil P.C. and, therefore no final decree can be maintained on such a defective preliminary decree was not at all raised. On the other hand, it is seen from the records that even in the final decree proceedings, the petitioner herein remained ex parte. Consequently, the final decree also came to be passed on 27-10-1984. It is needless to state that even an ex parte decree will operate as res judicata. If so, the present petitioner cannot now challenge that there is a defective preliminary decree and consequently there is no valid final decree. Consequently, the final decree also came to be passed on 27-10-1984. It is needless to state that even an ex parte decree will operate as res judicata. If so, the present petitioner cannot now challenge that there is a defective preliminary decree and consequently there is no valid final decree. I must also immediately point out that this is not a case where the decree can be challenged as a nullity because it is not the case of the petitioner that the Court, which passed the decree, has no jurisdiction, either territorial or otherwise, to entertain this action both on promissory note and on mortgage. As long as the Court had jurisdiction to entertain the suit, the decree passed by it is certainly valid. The ratio laid down in Kiran Singh v. Chaman Paswan, 1954 AIR(SC) 340, 1955 (1) SCR 117 , 1954 (2) MLJ 60, 1954 ALJ 551, 1965 KerLT 1195, 1954 All(LJ) 546 is that the nullity of a decree can be challenged even in execution. There it was found that the the Court which passed the decree did not possess jurisdiction and, therefore, the Supreme Court held that decree is but a nullity, I have already pointed out that the Court, which passed the decree, did possess ample jurisdiction to entertain the action and to pass a decree. Then this decision will not render any assistance to the learned counsel for the petitioner. So too, the other decision relied on by the learned counsel for the petitioner namely Sital Prasad v. Kishori Lal, 1967 AIR(SC) 1236, 1967 (3) SCR 101, 15 LawRep 716 will have no relevance in this case because there what was held by the Supreme Court is that when once the preliminary decree is set aside, the final decree passed on the strength of the preliminary decree has no independent existence. Thus I find the above objection is hardly tenable. 6. In the result, this civil revision petition is partly allowed, in that, the decree-holder is entitled to claim interest only at six per cent per annum as indicated above. In other respects, this revision petition is dismissed with proportionate costs. Petition partly allowed.