8.Learned counsel for the appellant attempted to contend that when the respondent was promoted in stop-gap arrangement as Junior Engineer I, he had given an undertaking to the appellant that on the basis of stop-gap arrangement, he would not claim promotion as of right nor would he claim any benefit pertaining to that post. The argument, to say the least, is preposterous. Apart from the fact that the Government in its capacity as a model employer cannot be permitted to raise such an argument, the undertaking which is said to constitute an agreement between the parties cannot be enforced at law. The respondent being an employee of the appellant had to break his period of stagnation although, as we have found earlier, he was the only person amongst the non-diploma-holders available for promotion to the post of Junior Engineer I and was, therefore, likely to be considered for promotion in his own right. An agreement that if a person is promoted to the higher post or put to officiate on that post or, as in the instant case, a stop-gap arrangement is made to place him on the higher post, he would not claim higher salary or other attendant benefits would be contrary to law and also against public policy. It would, therefore, be unenforceable in view of Section 23 of the Contract Act, 1872.”