On May 1, 1960, the State of Bombay }Vas bifurcated into two A States-Maharashtra and Gujarat. Prior to that date the six appellants in this appeal had joined Government service as Clerks-cum-typists. The Subordinate Secretariat Service was then divided into four grades (i) Clerk-cum-typist (ii) Junior Assistant (iii) Senior Assistant and (iv) Superintendent. Promotions were available from the lower tier to the upper one. When Gujarat became a separate State Government busiB ness in the Secretariat was divided into 9 departments separate in every respect so far as the Subordinate service was concerned. On October 12, 1960, by a Government Resolution the cadre of Superintendents became a common one covering all the departments in the Secretariat. Until then seniority was being determined departmentwise and promotions had also been regulated on the same basis in all c the four grades. Under the new arrangement promotion to the post of Superintendent was handled by the General Administration Department out of a common list of Senior Assistants. On September 25, 1964, under another resolution of Government the grades of Junior Assistants and Senior Assistants were merged into a single one known as Assistants w.e.f. October 1, 1964, and a common seniority list of D Government servants working as Assistants was prepared. A quota system was introduced for recruitment of Assistants. At one state, the ratio was 3: 1, promotees being the smaller proportion and later it was changed to 2: 1. On July 19, 1969, a seniority list of Assistants was prepared on quota basis and taking into account continuous officiation in the cadre of Assistants. The list was assailed before the High Court. E The court found by judgment dated March 9, 1972 that promo tees were in excess of the ratio and accordingly gave direction for a fresh list to be drawn up. On October 11, 1974, Government resolved to have a common cadre of Clerk-cum-typist and promotion to the post of Assistant was provided therefrom. In 1975, the October Resolution of Government was challenged before the High Court by filing two writ F petitions. In the meantime, in 1977, a set of rules known as the Gujarat Subordinate Secretariat Service (Seniority of Assistaht•) Rules, 1977 were framed under the proviso to Article 389 of the Constitution with retrospective effect from May 1, 1960. Rule 4 of the Rules laid down the principle for determining seniority by providing that seniority among the promotees Assistants inter se shall be fixed on the basis of their G length of service in the joint cadre of Clerk-cum-typist for all departments of the Secretariat as a whole. In December 1978 the two writ petitions were dismissed. The High Court held th~t the.object of the ~ules of 1977 was to equalise the chances of promotions to the selechon c_adre and since. the rules took care of the promotee officers by ensurmg non-revers10n, the rules were indeed not retrospective. H