JUDGMENT :

G.R. SWAMINATHAN, J.

1. This writ appeal is directed against the order dated 16.04.2018 allowing W.P. (MD) No. 15733 of 2014 filed by the respondents herein.

2. The respondents are working as vocational instructors in government higher secondary schools. They were placed in pre-revised scale of pay of Rs. 1400-2600 and revised scale of pay of Rs. 5500-175-9000. According to them, this fixation was erroneous since vide G.O.Ms. No. 840 dated 31.07.1990, the time scale of pay for vocational instructors having B.Sc. (Agri) qualification was directed to be fixed as Rs. 2000-3500 (equivalent to Rs. 6500-11100). They represented to the government seeking pay scale parity. The request was rejected by the Director of School Education, Chennai vide proceedings in Na. Ka. No. 24069/VI/V3/2014, dated 21.08.2014. Challenging the same, they filed W.P. (MD) No. 17533 of 2014. They contended that the issue raised by them had already been answered in their favour in W.A. (MD) No. 1344 of 2013 dated 14.08.2014 (The State of Tamil Nadu represented by its Secretary, School Education Department, Chennai and two others Vs. Vasimalai and another). The learned single Judge accepted the said contention and allowed the writ petition.

3. Questioning the same, the State filed this writ appeal. Before the Division Bench, the Special Government Pleader submitted that the previous order on which reliance was placed by the learned single Judge was clearly distinguishable on facts. Though the Division Bench was inclined to sustain the said contention, it noted that another Division Bench vide order dated 21.01.2019 in W.A. (MD) No. 1040 of 2019 had also followed Vasimalai. The factual matrix in W.A. No. 1040 of 2019 was similar to the facts on hand. Hence the matter was referred to the Full Bench by framing the following question:

"Is a Vocational Instructor recruited through Teachers Recruitment Board for the post created in G.O.Ms. No. 129 School Education (HS3) Department dated 18.05.1999 and G.O.Ms. No. 63, School Educational Department dated 13.03.2007 the scale of pay, having been prescribed in the ad hoc Rules issued in the G.O.Ms. No. 6, School Educational (VE) Department dated 04.01.2000, entitled to get higher salary on par with those who were appointed initially as double part time Vocational Instructors and brought under regular scale of pay subsequently but prior to the framing of ad hoc Rules?"

4. Learned Special Government Pleader appearing for the appellants reiterated the contentions set out in the memorandum of grounds of appeal and prayed for setting aside the order of the learned single Judge and for allowing the writ appeal.

5. Per contra, learned Senior Counsel appearing for the respondents submitted that there is absolutely no merit in this appeal. According to him, the learned single Judge had correctly applied the principle of equal pay for equal work. When some of the vocational instructors (Agriculture) are in the pay scale of Rs. 6500-11100, the respondents, who are discharging the very same duties and functions, cannot be placed in a lesser scale of pay (Rs. 5500-9000). He drew our attention to the decisions of the Hon'ble Supreme Court reported in Randhir Singh vs. Union of India, (1982) 1 SCC 618 and State of Punjab and Others vs. Jagjit Singh and Others, (2017) 1 SCC 148 to drive home his point.

6. We have carefully considered the rival contentions and gone through the material on record. To appreciate the facts of the case, it is necessary to briefly consider the historical background.

7. The Education Department of the government of Tamil Nadu introduced the higher secondary/plus-two system in 1978-79. It also permitted starting of vocational courses in higher secondary schools vide G.O.Ms. No. 1719, dated 14.09.1978. Vocational courses were started in 709 out of 874 higher secondary schools. The total number of courses