The writ petitioner was appointed as Secondary Grade Teacher on 17. 1972 in the Department of Adi Dravidar and Tribal Welfare and thereafter promoted as Primary School Headmaster. In the said post he was working from 1. 1988 to 30.11.1989 at Adi Dravidar Welfare Primary School, Nallur, Vridhachalam Taluk, Cuddalore District. He was reverted to the post of Secondary Grade Teacher in November, 1989 and again promoted as Primary School Headmaster on 16. 1999 and he retired from service on 38. 2004 on attainment of age of superannuation.

2. Before 6. 1988, the posts of Primary School Headmaster and Secondary Grade Teacher were treated as transferable and interchangeable, since both carried the same scale of pay. The persons who were Secondary Grade Teachers posted in exigencies as Primary School Headmasters before 6. 1988 were granted special allowance. It was by G.O.Ms.No.666, dated 27. 1989, as per the V Pay Commission recommendation, the post of Primary School Headmaster was separated with higher scale of pay than the Secondary Grade Teacher with effect from 6. 1988.

3. By a proceeding of the Director of Elementary Education dated 12. 1990, the persons who were holding