BHAGWATI, C. J. :- The petitioners are owners of different pieces of land forming one compact block situate at village Vasana, City Taluka, Ahmedabad District. The third respondent society is a co-operative housing society formed with the object of enabling its members to construct houses and registered under the Bombay Co-operative Societies Act, 1925 - now deemed to be registered under the Gujarat Co-operative Societies Act, 1961. The petitioners' lands being well situate, the third respondent society moved the State Government to acquire the petitioners' lands for construction of houses by its members and the State Government accordingly issued a notification dated 20th May, 1961 under Section 4 stating inter alia that the petitioners' lands were likely to be needed for a public purpose, namely, for construction of houses for members of Shri Yogeshwar Co-operative Housing Society Ltd. Within thirty days of the issue of this notification some of the petitioners filed their objections against the proposed acquisition of their lands and the Collector after holding an inquiry made his report to the State Government under Section 5-A, sub-section (2). The petitioners who are owners of survey Nos. 7, 8, 14 and 17, apprehending that the State Government will immediately proceed to issue a notification under Section 6 in respect of their lands thereupon filed Special Civil Application No. 564 of 1962 challenging the power of the State Government to acquire for construction of houses for members of a co-operative housing society and seeking to restrain the State Government from proceeding further under the notification dated 20th May, 1961. On the petition being admitted an interim injunction was sought but it was refused and the State Government after considering the report of the Collector under Section 5-A, sub-section (2), issued a notification dated 29th April, 1963 under Section 6 which in so far as is material was in the following terms :

"......Whereas the Government of Gujarat is satisfied ...... that the said lands are needed to be acquired at the public expense for the public purpose specified in column 4 of the Schedule hereto.

It is hereby declared under the provisions of Section 6 of the said Act that the lands are required for the public purpose specified in Column 4 of the Schedule hereto."

The public purpose specified in column 4 was "for a Housing Scheme undertaken by Shri Yogeshwarnagar Co-operative Housing Society Limited, Ahmedabad, with the sanction of the Government." Though this statement of the public purpose in the notification dated 29th April, 1963 was worded slightly differently from that contained in the notification dated 20th May, 1961, the case of the respondents was that there was no difference in substance as the housing scheme referred to in the notification dated 29th April, 1963 was a housing scheme for the members of the third respondent society and not for the public. It may be stated here that prior to the issue of the notification dated 29th April, 1963, a resolution dated 21st December, 1962 was passed by the Government sanctioning a nominal contribution of Re. 1/- towards the cost of acquisition and that is why the recital in the said notification stated that "......... the said lands are needed to be acquired at the public expense". Notices under Section 9, sub-section (1) were thereafter served on the petitioners and the Special Land Acquisition Officer after holding the requisite inquiry made an award dated 21st December, 1963 determining the amount of compensation payable to the petitioners in each of these petitions. Possession of the respective lands was then demanded by the Government from the petitioners. The petitioners who are owners of Survey Nos. 7 to 9, 12 to 17 and 19 to 22 thereupon preferred Special Civil Application No. 1100 of 1963 challenging the validity of the notification dated 29th April, 1963. Nothing transpired thereafter until 15th April, 1966 when the Gover