JUDGMENT

BHAGWATI, J. :— This appeal by certificate is directed against the judgment of the High Court of Delhi allowing the writ petition of respondent No. 1 and striking down the validity of the seniority list issued by the appellant placing the first respondent below respondent Nos. 3 to 9 in the seniority list. The controversy arising in the appeal lies in a narrow compass but in order to arrive at its correct determination, it is necessary to state briefly a few facts leading to the filing of the appeal.

2. The first respondent was recruited to the Indian Administrative Service through a competitive examination held in 1955 and according to R. 3(3)(a) of the Indian Administrative Service (Regulation of Seniority) Rules, 1954 (hereinafter referred to as the Seniority Rules), he was assigned the year 1956 as the year of allotment to the Service. He was posted in a junior post on recruitment through the Indian Administrative Service and on 21st August, 1961 he started officiating in a senior post. Respondent Nos. 3 to 9 were on the other hand members of the Gujarat State Civil Service and they were promoted to the Indian Administrative Service and they started officiating continuously in the senior post in the Service w.e.f. 9th June 1961 so far as respondent Nos. 3 to 7 were concerned and with effect, from 29th August 1961 so far as the remaining respondents, namely, respondent Nos. 8 and 9 were concerned. The year of allotment given to respondent Nos. 3 to 9 was the same as that of respondent No. 1, namely, 1956 and that was given in accordance with the provisions of R. 3(3)(b) of the Seniority Rules. The seniority amongst direct recruits through competitive examination and promotees from the State Civil Service was governed by the Seniority Rules and according to the first respondent, since they were all assigned the same year of allotment, the first respondent as a direct recruit through a competitive examination was entitled to rank higher in seniority than respondent Nos. 3 to 9 who were promoted from the State Civil Service. But, when the gradation list as on 1st January, 1963 was issued by the Government of India, the first respondent found that the Government of India had placed respondent Nos. 3 to 9 as senior to him in the gradation list, on the ground that they had started officiating in a senior post in the Service earlier than the first respondent. The first respondent thereupon made several representations to the Government of India against the fixation of his seniority vis-a-vis respondent Nos. 3 to 9 but the Government of India ultimately rejected his representation by a communication dated 7th October, 1966. The first respondent thereupon filed a writ petition in the High Court of Delhi challenging the validity of the gradation list showing him as junior to respondent Nos. 3 to 9. The writ petition came up for bearing before a single Judge of Delhi High Court and the learned Judge rejected the contentions of the first respondent and dismissed the writ petition. Respondent No. 1 thereupon preferred a Letters Patent Appeal before a Division Bench of the Delhi High Court and the Division Bench did not agree with the view taken by the learned single Judge and held that the first respondent was entitled to seniority over respondent Nos. 3 to 9 and that the Government of India was wrong in placing him below respondent Nos. 3 to 9 in the gradation list. The Division Bench on this view allowed the Letters Patent Appeal and issued a writ directing that the gradation list be corrected by showing the first respondent as senior to respondent Nos. 3 to 9. The Union of India thereupon preferred the present appeal on the basis of certificate granted under Art. 133(1)(c) of the Constitution.

3. The short question which therefore arises for consideration is as to the relative seniority of the first respondent vis-a-vis respondent Nos. 3 to 9. Since the only rules in force for determining inter se seniority of officers in the