JUDGMENT 1. These two writ appeals are interlinked and are disposed of by this common Judgment M. C. Chacko filed O. P. No. 2333 of 1989, wherein Aleyamma Sebastian (petitioner in O. P. No. 31,74 of 1989) was third respondent. Similarly, in the Original Petition filed by Aleyamma Sebastian, Chacko was fifth respondent, 2. Aleyamma Sebastian is an under-graduate teacher. Chacko is a graduate with B. Ed. degree. Post of Headmastership of Tharakkal A. U. P. School (hereinafter referred to as the institution) fell vacant on 1st April 1988. Chacko had completed 5 years after acquisition of graduation. But he had not completed 5 years after acquisition of B. Ed. degree. R.45 of Chapter XIV-A of Kerala Education Rules, 1959 (in short, the Rules) framed under Kerala Education Act, 1958 (in short, the Act) was amended with effect from 10th January 1989. After amendment, qualification prescribed is that one should have 5 years experience after acquisition of B. Ed. degree. R.45, as it stood before amendment, provided that when the post of Headmaster of complete U. P. school is vacant or when an incomplete U. P. school becomes a complete U. P. school, the post shall be filled up from among qualified teachers on the staff of school or schools under educational agency, and if there is a graduate teacher with B. Ed. or other equivalent qualification and who has got at least 5 years experience ia teaching after acquisition of B. Ed. degree, he may be appointed as Headmaster, provided he has got a service equal to half of the period of service of the senior most undergraduate teacher. It further stated that if graduate teachers with aforesaid qualification and service are not available in school or schools under same educational agency, senior most primary school teacher with S. S. L. C. or equivalent and T. T.C. issued by Board of Public Examination, Kerala or T.C.H. issued by Karnataka Secondary Education Examination Board, Bangalore or a pass in Pre degree examination with Pedagogy as an elective subject conducted by University of Kerala or any other equivalent training qualification prescribed for appointment as Primary School Assistant may be appointed. Amendment was made with effect from 10th January 1989, and after that, the expression "after acquisition of B. Ed. degree" was substituted for the expression "after graduation". Amendment was made with effect from 10th January 1989, and after that, the expression "after acquisition of B. Ed. degree" was substituted for the expression "after graduation". In view of amendment, position is that one should have five years experience after acquisition of B. Ed. degree. Educational authority selected Aleyamma Sebastian for appointment. She filed O. P. No. 3174 of 1989 for enforcement of said decision. In O. P. No. 2333 of 1989, Chacko challenged the order in favour of Aleyamma Sebastian. 3. Only question that was raised by Chacko was that amended provision cannot have retrospective operation. Learned Single Judge held that the only question that required adjudication was whether amendment can be considered retrospective or not. Before amendment, question arose whether 5 years' experience mentioned in R.45 should be after graduation or after acquisition of B. Ed. degree. In Raghavan v. State of Kerala 1987 (2) K. L. T. 942 a Full Bench of this Court held that 5 years' experience mentioned in R.45 is after graduation. According to State, amendment to R.45 was made making it operative with retrospective effect Learned Single Judge held that amendment was intended for removal of doubt and Aleyamma Sebastian is a rightful claimant for the post of Headmaster. 4. The two writ appeals have been filed by Chacko questioning correctness of said conclusion. Stand of counsel for appellant is that the S. R. O. itself said that it shall come into force at once and, therefore, cannot be treated to have retrospective nature. There is nothing to show that amendment was intended to have retrospective operation and for removal of doubts. With reference to the Explanatory Note, learned counsel for Aleyamma Sebastian submitted that it was clearly stated therein that in order to remove doubts, above amendment was made. 5. Factual position is undisputed. In the notification, it is stated that amended rule shall come into force at. once. It is equally clear from the S.R.O. containing the amendments that in order to remove doubts in interpreting R.45, above amendment was issued. Therefore, amendment was intended to remove doubts. 6. It is a cardinal principle of construction that every statute is prima facie prospective unless it is expressly or by necessary implication made to have retrospective operation. once. It is equally clear from the S.R.O. containing the amendments that in order to remove doubts in interpreting R.45, above amendment was issued. Therefore, amendment was intended to remove doubts. 6. It is a cardinal principle of construction that every statute is prima facie prospective unless it is expressly or by necessary implication made to have retrospective operation. But the rule in general is applicable where object of the statute is to affect vested rights or to impose new burdens or to impair existing obligations. Unless there are words in the statute sufficient to show the intention of legislature to affect existing rights, it is deemed to be prospective only 'nova constitutio futuris formam imponere debet non praeteritis' (A new law ought to regulate what is to follow, not the past). In the words of Lord Blanesburg, 'provisions which touch a right in existence at the passing of statute are not to be applied retrospectively in the absence of express enactment or necessary intendment' [see Delhi Cloth Mills and General Co. Ltd. v. C. I.T. A.I R.1927 P.C. 242]. Every statute, it has been said, observed Lopes, L. J., which takes away or impairs vested rights acquired under existing laws, or creates a new obligation or imposes a new duty, or attaches a new disability in respect of transactions already past, must be presumed to be intended not to have a retrospective effect [see Re Pulborough Parish School Board Election, Bourke v. Nutt (1894) 1 Q.B. 725]. As a logical corollary of the general rule, that retrospective operation is not taken to be intended unless that intention is manifested by express words or necessary implication, there is a subordinate rule to the effect that a statute or a section in it is not to be construed so as to have larger retrospective operation than its language renders necessary [see Reid v. Reid (1886) 31 Ch. D. 402]. In other words close attention must be paid to the language of statutory provision for determining the scope of retrospectivity intended by law making authority [see Union of India, v. Raghubir Singh A.I.R. 1989 S.C. 1933]. D. 402]. In other words close attention must be paid to the language of statutory provision for determining the scope of retrospectivity intended by law making authority [see Union of India, v. Raghubir Singh A.I.R. 1989 S.C. 1933]. But if literal reading of provision giving retrospectively produces absurdities and anomalies, a case not prima facie within the words may be taken to be covered, if purpose of the provision indicates that intention was to cover it [see Union of India v. Filip Tiago De Gama of Vedem Vasco De Gama A.IR. 1990 S.C. 981]. Inhibition against retrospective construction is not a rigid rule and must vary Secundum materium [see Barber v. Pigden (1937) 1 All E.R. (CA) 125]. It is not necessary that an express provision be made to make a statute retrospective and the presumption against retrospectivity may be rebutted by necessary implication especially in a case where new law is made to cure an acknowledged evil for the benefit of community as a whole [see Mithilesh Kumari v. Prem Bihari Khare A.I.R. 1989 S.C. 1247]. Real issue in each case is as to scope of particular enactment having regard to its language and the object discernible from statute read as a whole. Rule that an Act of Parliament is not to be given retrospective effect applies only to statutes which affect vested rights. It does not apply to statutes which only alter the form of procedure or admissibility of evidence or the effect which the courts give to evidence. If the new Act affects matters of procedure only, then, prima facie, it applies to all actions pending as well as future. In stating the principle that 'a change in the law of procedure operates retrospectively and unlike the law relating to vested right is not only prospective', Supreme Court has quoted with approval the reason of the rule as expressed in Maxwell: Interpretation of Statutes, 11th Edition, p. 216: "No person has a vested right in any course of procedure. In stating the principle that 'a change in the law of procedure operates retrospectively and unlike the law relating to vested right is not only prospective', Supreme Court has quoted with approval the reason of the rule as expressed in Maxwell: Interpretation of Statutes, 11th Edition, p. 216: "No person has a vested right in any course of procedure. He has only the right of prosecution or defence in the manner prescribed for the time being by or for the Court in which the case is pending, and if, by an Act of Parliament the mode of procedure is altered, he has no other right than to proceed according to the altered mode" [see Anant Gopal Sheorev v. State of Bombay A.I.R. 1958 S.C. 915, Union of India v. Sukumar Pyne A.I.R. 1966 S.C. 1206 and Gurbachan Singh v. Satpal Singh A.I.R. 1990 S.C. 209]. 7. Presumption against retrospective operation is not applicable to declaratory statutes. As stated in CRAIES and approved by Supreme Court: For modern purposes a declaratory Act may be defined as an Act to remove doubts existing as to the common law, or the meaning or effect of any statute. Such Acts are usually held to be retrospective. Usual reason for passing a declaratory Act is to set aside what parliament deems to have been a judicial error, whether in the statement of the common law or in the interpretation of statutes. Usually, if not invariably, such an Act contains a preamble, and also the word 'declared' as well as the word 'enacted' [see Central Bank of India v. Their Workmen A.I.R. 1960 S.C. 128]. In Justice G. P. Singh's (Sixth Edition, 1996) "Principles of Statutory Interpretation" under the heading "Declaratory Statutes", the learned author has summed up the above position, which was held to be in line with decisions of apex Court as well as English decisions [see C.I.T. v. M/s Podar Cement Pvt, Ltd. A.I.R. 1997 S.C. 2523]. But use of the words 'it is declared' is not conclusive that the Act is declaratory for these words may, at times, be used to introduce new rules of law and the Act in the latter case will only be amending the law and will not necessarily be retrospective [see Har ding v. Queensland Stamp Commissioners (1898) A.C. 769 (P.C.)]. But use of the words 'it is declared' is not conclusive that the Act is declaratory for these words may, at times, be used to introduce new rules of law and the Act in the latter case will only be amending the law and will not necessarily be retrospective [see Har ding v. Queensland Stamp Commissioners (1898) A.C. 769 (P.C.)]. In determining, therefore, the nature of the Act, regard must be had to the substance rather than to the form. If a new Act is 'to explain' an earlier Act, it would be without object unless construed retrospective [see R. v. Dursley (Inhabitants) (1832) 110 E.R. 168]. An explanatory Act is generally passed to supply an obvious omission or to clear up doubts as to the meaning of the previous Act. It is well settled that if a statute is curative or merely declaratory of previous law retrospective operation is generally intended [see Channan Singh v. Jai Kuar A.I.R. 1970 S.C. 349]. In the absence of clear words indicating that the amending Act is declaratory, it would not be so construed when the pre-amended provision was clear and unambiguous. An amending Act may be purely clarificatory to clear a meaning of a provision of the principal Act which was already implicit. A clarificatory amendment of this nature will have retrospective effect. A validating Act may even make ineffective Judgment and orders of competent Courts provided it by retrospective legislation removes the cause of invalidity which had led to those Judgments [see Bhubaneswar Singh v. Union of India J.T. 1994 (5) S.C. 83], If a statute merely declares the previous law retrospective operation would be more right, than the legislature which may prejudicially affect the past rights and actions. When factual position is considered in the background of the legal position set out above, it is clear that substitution of expression "after acquisition of B.Ed, degree" for the expression "after graduation" made on 10th January 1989, was intended to be retrospective and as a declaratory measure, said amendment was brought in. Conclusions of learned Single Judge suffer from no infirmity to warrant interference. Appeals fail and are dismissed.