JUDGMENT : A.K. Jayasankaran Nambiar, J. The State of Kerala is the appellant in all these appeals, aggrieved by the common judgment dated 18.03.2021 of the learned single judge in W.P(C) No.1033/2020 and connected cases and the subsequent judgments of the learned single judge following the former judgment. The short issue that was adjudicated by the learned single judge was the validity of an amendment effected to Rule 14E (b) of Part III Kerala Service Rules [KSR], to the extent it stipulated that only regular service rendered by teachers in private aided colleges in the State, prior to the regular service rendered by them in the aided/government colleges from where they superannuated, would be reckoned for the purposes of computation of their pensionary benefits. The brief facts necessary for disposal of these writ appeals are as follows: The writ petitioners were all persons who had rendered service in leave vacancies in various private aided colleges in the State, prior to commencing regular service in the establishment from which they subsequently retired on superannuation. In their writ petitions, they were aggrieved by the stand of the respective authorities of the State government, based on the amendments effected to Rule 14E (b) of Part III KSR in 2009, that they could not reckon the prior service rendered by them in leave vacancies in private aided colleges in the state, for the purposes of computing their pensionary benefits. The writ petitioners pointed out that while the erstwhile provisions of Part III KSR, that was made applicable to them through the relevant provisions of the University statutes that governed their conditions of service and pensionary benefits, clearly provided for reckoning their regular service in the establishment from which they retired on superannuation, for the purposes of pensionary benefits, various government orders issued by the State Government from time to time had permitted the addition of prior service rendered in aided private colleges in the State, to the former, for the purposes of determining their entitlement to pensionary benefits. They contended, therefore, that the impugned amendment that was effected in 2009, purportedly to provide a statutory footing to the executive orders aforementioned, ran counter to the said objective and was ultra vires the Kerala Service Rules framed by the State Government pursuant to the power granted under Article 309 of the Constitution. 2. They contended, therefore, that the impugned amendment that was effected in 2009, purportedly to provide a statutory footing to the executive orders aforementioned, ran counter to the said objective and was ultra vires the Kerala Service Rules framed by the State Government pursuant to the power granted under Article 309 of the Constitution. 2. Through the counter affidavits filed on behalf of the State government in the writ petitions, it was pointed out that the impugned amendment to Rule 14E (b) of Part III KSR was effected so as to give a statutory basis to the Government Orders that had earlier held the field and, in that sense, there was no substantial change effected to the conditions of service of the teachers concerned. Reference has been made to the earlier and subsequent Government orders issued in this connection and also to the judgment of a Division Bench of this Court in Shameer Ali v. Deputy Director of Collegiate Education – [ 2018 (3) KLT 925 ], wherein this Court had held that while aided school service put in by government college employees prior to their entry in government service had to be reckoned for the purposes of pensionary benefits, it would nevertheless be subject to the six specific conditions mentioned in Rule 14E of Part III KSR. 3. The learned single judge who considered the issue found that the impugned amendment, to the extent it included the word ‘regular’ to qualify the prior service rendered by teachers in aided colleges, prior to their service in the aided college from which they retired on superannuation, for the purposes of pensionary benefits, went against the stated objective of the amendment that it only gave effect to the executive orders that held the field till then. The learned judge found that the earlier government orders had not qualified the service that was eligible for being counted for pensionary purposes and hence the service could not have been qualified while continuing the said benefit through a statutory provision. The learned judge found that the earlier government orders had not qualified the service that was eligible for being counted for pensionary purposes and hence the service could not have been qualified while continuing the said benefit through a statutory provision. The learned judge also relied on the provisions of Rule 20 of Part III KSR, and the proviso thereto, to hold that past service put in by government employees and aided school/college teachers in Panchayath/Municipal common service and Universities prior to their entry in State Government service or Aided School/College service had to be reckoned as qualifying service for pensionary benefits and hence there could not be a different yardstick stipulated under Rule 14E (b) of Part III KSR. The writ petitions were therefore allowed by striking down the expression ‘regular’ in clause (i) of clause (b) of Rule 14E, Part III KSR and its applicability with effect from 30.07.1979. It was held that the amended provision would apply only prospectively from 28.08.2009 as was done in the case of a similar amendment brought about in Rule 14E (a) by the notification dated 10.08.2018. 4. We have heard the learned Advocate General Sri. Gopalakrishna Kurup, duly assisted by the learned senior Government Pleader Sri. A.J.Varghese on behalf of the appellants in these writ appeals, Sri. P.C. Sasidharan, the learned Standing counsel for the Calicut University, Sri.Thomas Abraham, the learned Standing counsel for the Kerala University, Sri.Surin George Ipe, the learned Standing counsel for the M.G. University, Adv. Sri.M.S.Radhakrishnan Nair, Adv. Sri.Siji Antony, Adv. Sri.K.M. Kurian, Adv. Smt.Vineetha Susan Thomas, Adv. Sri.B.Mohanlal, Adv. Sri.S.Harikrishnan, Adv. Sri.Baby Issac Illickal, Adv. Sri.M.M.Monaye, Adv. Sri.Benoy Thomas, Adv. Sri.S.Muhammed Haneeff, Sri. Babu Varghese, the learned senior counsel duly assisted by Adv. Sri.C.V.Alexander, Adv. Sri.A.K.Alex, Adv. Sri.Arun B. Varghese, Adv. Sri.V.A.Muhammed and Adv. Sri.Murali Pallath for the respondents in these writ appeals. 5. On a consideration of the rival submissions, we find that it is not in dispute in these appeals that the writ petitioners were essentially aggrieved by the non-inclusion of their prior service rendered in leave vacancies in private aided colleges, prior to their entry into regular service in either the same or different aided/government colleges from where they retired on superannuation, in the service period that qualified for the grant of pensionary benefits in terms of Part III KSR. Their challenge to the amendment effected to Rule 14E (b) Part III KSR was premised on the assumption that the said provision, which dealt with reckoning of past service for pensionary benefits, took in even service that was rendered in leave vacancies. It was therefore that they pointed to the government orders that earlier held the field, and contended that the amendment to the KSR, that was purportedly effected to provide a statutory basis for the benefits intended for them, frustrated that intention by qualifying the service as ‘regular’ service and further, depriving them of accrued/vested rights through a retrospectivity accorded to the amendment. We might point out at the very outset that we find this assumption to be erroneous, and that a challenge to the statutory provisions could not have been maintained at the instance of the writ petitioners. Rule 14E(b) of Part III KSR reads as follows: “14E. (a) xxxxxxxxxxxxx xxxxxxxxxxxxxx xxxxxxxxxxx (b) Aided private college service, both teaching and non-teaching, of Government employees prior to their entry in Government service shall qualify for pensionary benefits, subject to the following conditions, namely:- (i) The actual period of regular full time service rendered from the date of actual introduction of Direct Payment System in the aided private college shall be counted. (ii) Service rendered prior to the introduction of Direct Payment System in any private college shall be counted only for the period of those incumbents who have been paid salary under grant-in-aid scheme introduced with effect from 1965. (iii) In cases of resignation of the appointment in private college service for the purpose of taking up appointment in Government, break, if any, between the private college service and the Government service shall not exceed the joining time admissible under the service rules, plus public holidays. Service prior to resignation for other purposes shall not be counted. (iv) The Government contribution if any, to their Provident Fund Account in respect of their aided private college service shall be refunded to Government. (v) The Management's share of contribution if any in Provident Fund Account in respect of aided private college staff shall be credited to Government. In such cases, a certificate in the following form shall be recorded in the Service Book by the Head of Institution in which the incumbent had worked duly countersigned by the Head of the Department. (v) The Management's share of contribution if any in Provident Fund Account in respect of aided private college staff shall be credited to Government. In such cases, a certificate in the following form shall be recorded in the Service Book by the Head of Institution in which the incumbent had worked duly countersigned by the Head of the Department. “Certified that the Governments'/Managements' share of contribution with interest thereon which should otherwise have gone to the employee has not been/shall not be paid to him/her but has been/shall be credited to Government.” The certificate regarding the crediting of Managers' contribution is not necessary when contributions are to be paid back to the Management under rules. (vi) For counting the aided private college service, a certificate in the following form shall be recorded in the Service Book by the Head of the Institution in which the incumbent had worked duly countersigned by the Head of the Department. “Service has been verified with reference to the initial records such as attendance registers, acquittance rolls, pay bills etc., and is qualifying for pension.” 6. Prior to the introduction of Rule 14E (b) in Part III KSR, the provisions for inclusion of prior aided college service for pensionary benefits were to be found in various Government orders issued from time to time. Vide G.O.(Ms.)No.191/77/H.Edn dated 05.12.1977, private college service of government college teachers was permitted to be counted for retirement benefits subject to the conditions specified therein. G.O.(P)No.670/79/Fin. dated 30.07.1979 extended the said benefit to government employees other than government college teachers. Later, by G.O.(P)No.319/85/Fin. dated 05.06.1985, prior government service of private college teaching/non-teaching staff was permitted to be counted for pension. Thereafter, through G.O.(P)No.543/89/Fin. dated 20.11.1989, the government permitted provisional service, with or without break, to be reckoned as qualifying service for pension. G.O.(P)No.540/94/Fin. dated 30.09.1994, although issued in the context of reckoning the provisional service that would count for the purposes of increment, gives a clear indication that the provisional service envisaged in the government orders is one rendered in terms of Rule 9 (a) (i) of Part II Kerala State & Subordinate Service Rules [KS&SSR]. What is significant, however, is that the various government orders issued in the context of defining the service, other than regular service, that would qualify for pensionary benefits, did not at any point in time include service rendered in leave vacancies. Further, through G.O. (P)No.3116/98/Fin. What is significant, however, is that the various government orders issued in the context of defining the service, other than regular service, that would qualify for pensionary benefits, did not at any point in time include service rendered in leave vacancies. Further, through G.O. (P)No.3116/98/Fin. dated 15.12.1998, the benefit of reckoning provisional service for pensionary benefits was cancelled with effect from 01.10.1994 with the condition that past cases would not be reopened. Through G.O.(P) No.2357/99/Fin. dated 25.11.1999, it was clarified that provisional service that counted for increment till 30.09.1994 would also be reckoned for pension irrespective of dates of retirement after 20.11.1989 and that provisional service after 01.10.1994 would not be reckoned as qualifying service for pension. It was also clarified that cases of retirement from service during the period from 01.10.1994 to 15.12.1998, and pensionary claims already sanctioned would not be re-opened. 7. A mere perusal of the various government orders referred above would clearly indicate that the service that was once considered for inclusion in the qualifying service for pension was the provisional service envisaged under Rule 9 (a) (i) of the KS&SSR. Although such provisional service, that is rendered against a post that the incumbent holds temporarily, on account of his not being eligible to occupy the sanctioned post on regular basis, would not ordinarily qualify for the grant of pensionary benefits, it is within the discretion of the Government to include such service for pensionary benefits. In other words, the extension of pensionary benefits to a category of persons who would otherwise not be entitled to pension as per the rules is within the discretion of the government. While it may be true that the government chose to include provisional service rendered against sanctioned posts till regular hands were appointed, in the qualifying service for pension, it does not follow that the government must, on the principles of equality, extend the same benefit to service rendered in a leave vacancy especially when the lien to the post, even during the leave period, is held by a person other than the writ petitioners herein. 8. In the case of provisional service rendered against a sanctioned post, the incumbent to the post obtains a limited lien to the post, co-terminus with his engagement on provisional basis. 8. In the case of provisional service rendered against a sanctioned post, the incumbent to the post obtains a limited lien to the post, co-terminus with his engagement on provisional basis. As against this, the distinguishing feature of a service rendered in a leave vacancy is the fact that the lien to the post is all along held by another person, in whose absence from the place of work, the incumbent gets an opportunity to work in the post. The scheme under the KSR, read with the Government Orders issued from time to time, clearly indicates that it is the occupancy of a post together with a lien thereto – either limited or absolute – that entitles the lien holder to the pensionary benefits attached to that post. The person appointed in a leave vacancy merely officiates or occupies that post till the original 9. When the issue is considered in the light of the above discussion, it becomes apparent that even in the absence of the word ‘regular’ that qualified the service that was included for the purposes of pensionary benefits in Rule 14E (b), the service envisaged thereunder was only such provisional or other service that conferred a lien to the post on the employee concerned. The claim of the writ petitioners being in respect of service rendered in leave vacancies, they were not in any way entitled to the beneficial provisions of either the government orders referred above, or to the provisions of Rule 14E (b) and, in that sense, they never obtained any vested right to count their service in leave vacancies for the pensionary purposes. As observed in a recent judgment of the Supreme Court in Manish Kumar v. Union of India–[ (2021) 5 SCC 1 ], rights are ‘vested’ when the right to enjoyment, present or prospective, has become the property of some particular person or persons as present interest. A mere expectancy of future benefits, or contingent interest in property founded on anticipated continuance of existing laws, does not constitute vested rights. A right vests when all the facts have occurred which must by law occur in order for the person in question to have the right. A mere expectancy of future benefits, or contingent interest in property founded on anticipated continuance of existing laws, does not constitute vested rights. A right vests when all the facts have occurred which must by law occur in order for the person in question to have the right. In the instant case, the writ petitioners could not point to any provision, either in the government orders or under the statutory rules, that conferred on them a right to include service rendered in leave vacancies in the qualifying service reckoned for pensionary benefits. A challenge to the vires of an amendment to the Rule 14E(b) of Part III KSR which in no way affect them, could not have been maintained at their instance. 10. After the hearing in these appeals was concluded, the learned counsel for the respondents/writ petitioners in W.A.Nos. 1237/2021, 1280/2021 and 1272/2021 brought to our notice a judgment dated 01.12.2021 of the Supreme Court in Dr. G. Sadasivan Nair v. Cochin University of Science & Technology & Ors–[CA No.6994/2021] to support his argument for inclusion of service rendered in leave vacancies in the qualifying service for pension. On a reading of the said judgment, however, we find that the issue considered by the Supreme Court was whether the benefit of reckoning the service as an advocate, prior to joining university service, could be denied to a person based on an amendment to the statutory rule that was brought in subsequent to his joining the university. The court took note of the fact that the university had granted the benefit to another employee who had joined the university prior to the amendment and hence there was no justification in denying the same benefit to the appellant before it. We do not see how the said judgment can come to the aid of the respondents herein more so when they have not been able to refer us to any provision in law whereby their service in leave vacancies can be counted for pensionary benefits. There is also no reference to any such provision in the argument notes that were submitted to us on behalf of the learned senior counsel Sri. Babu Varghese, who appeared on behalf of the respondent writ petitioners in W.A.No.1575/2021. There is also no reference to any such provision in the argument notes that were submitted to us on behalf of the learned senior counsel Sri. Babu Varghese, who appeared on behalf of the respondent writ petitioners in W.A.No.1575/2021. Further, we note that in the said Writ Appeal and in W.A.Nos.1230/2021 and 1565/2021 the vacancy in which the services were rendered includes deputation vacancy which in the context of the lien held is conceptually the same as a leave vacancy and accordingly the same principle as above would apply to find against the writ petitioners therein. 11. While the above discussion would be sufficient to repel the challenge of the writ petitioners, it is also significant that none of the writ petitioners produced material to suggest that they had complied with the conditions stipulated in Rule 14E (b) for the grant of benefits thereunder, even assuming that they qualified for the receipt of such benefits. Compliance with the said conditions is a pre-condition for obtaining the benefits under the Rule, as held by the division bench decision of this court in Shameer Ali(supra). In the result, we find ourselves unable to uphold the impugned judgment of the learned single judge. The writ appeals are therefore allowed by setting aside the impugned judgments of the learned single judge and dismissing the writ petitions.