The Housing Authority of the City of Los Angeles, by petition filed on August 4, 1952, seeks to have the members of the City Council of the City of Los Angeles held in contempt of this court for their alleged failure to comply with the terms of a peremptory writ of mandate issued *684by this court on June 27, 1952. (Housing Authority v. City of Los Angeles, 38 Cal.2d 853 [243 P.2d 515], certiorari denied, 344 U.S. 836 [73 S.Ct. 46, 97 L.Ed. 41].) That proceeding will be referred to in this opinion as the mandate proceeding.
The mandate proceeding was brought to test the validity of the city’s action of December 26, 1951, attempting to abrogate, cancel, and rescind the agreements authorized by Ordinance No. 95,222 adopted on August 8, 1949. By that ordinance the city approved construction of a 10,000-unit low-rent housing project in cooperation with the housing authority of the city and the Public Housing Administration of the United States pursuant to the State Housing Authorities Law and Housing Cooperation Law (Health & Saf. Code, §§ 34200-34368, 34500-34521). The housing authority successfully sought to have this court declare invalid the city’s attempted withdrawal of its approval of the project and the attempted cancellation of its agreements, and to compel the city to perform the acts required by the cooperation agreement and other agreements entered into by it with the housing authority for carrying out the contemplated project. We. determined that since the city had approved the project, and the housing authority and the Public Housing Administration had made binding contractual commitments and advances in respect to the project, the city was without power, in the absence of express statutory authority, to withdraw its approval or to abrogate its agreements. A writ of mandate issued “directing the respondents to perform the terms of the agreements entered into with the petitioner and to proceed in the fulfillment of its obligations thereunder.”
In the present proceeding the housing authority alleged various matters as to which it was claimed the city had agreed to take action and as to which it had refused to proceed, in violation of this court’s order in the mandate proceeding. An order was issued directing the individual members of the city council to show cause why they should not be adjudged in contempt of this court for failing, neglecting, and refusing to obey the peremptory writ of mandate. By reason of a stipulation of the parties on the return to the order to show cause, the only charge remaining to be considered is the failure of the city to complete annexation proceedings that would include in the site selected for the West Los Angeles (Cal. 4-21) project a county strip entirely surrounded by incorporated territory. The facts relating to the failure *685to complete the proceeding to annex the county “island” are undisputed.
On November 22, 1950, the city council approved and adopted a report of its Veterans’ Affairs and Housing Committee recommending approval of the authority’s proposal to acquire 11 sites including the one now in question. The map of that site, submitted by the authority with its proposal, showed the presence of the county island. Thereafter, an application to the planning commission for a conditional use of the site for a housing project was made. The description of the site recited that it lay “partly in unincorporated territory of the County of Los Angeles,” and an attached report pointed out that there should be no difficulty in acquiring title to the county strip and annexing it to the city. On April 26, 1951, the application was granted by the planning commission. An appeal was taken to the city council and denied by that body on June 26, 1951. Thereafter the authority acquired title to the property comprising the county island and requested that the city council annex it. The usual procedure was promptly instituted, and after receiving reports from various city departments, the coordinating board unanimously recommended approval of the proposed annexation. The council referred this recommendation to its planning committee, which reported back on October 24, 1951. It reported that the coordinating board had recommended annexation “as requested by the Los Angeles Housing Authority,” and had advised that “the annexation of this strip would conform to the City’s policy of absorbing county islands, thereby creating a more regular city boundary line. . . .” The council then adopted its committee’s report recommending annexation, and ordered proceedings to that end commenced. Thereafter, however, the city attempted to rescind its cooperation agreement and terminate the development of all public housing projects thereunder.
The city contends not only that it has not contracted to annex territory, but that under the provisions of the Housing Authorities Law (Health & Saf. Code, § 34200 et seq.) and the Housing Cooperation Law (Health & Saf. Code, § 34500 et seq.) it has no power to do so. The city relies on section 34208 of the Health and Safety Code limiting the authority’s area of operation to the city and section 34509 permitting the city to cooperate in the planning, construction, and operation of housing projects only when they are *686located “within the area in which it is authorized to act.” It also points out that there is no express statutory provision authorizing a city to annex territory pursuant to a cooperation agreement with a housing authority.
It may be conceded that under the foregoing provisions the city and the authority do not have power to contract to develop a housing project completely outside the city limits or agree that the city shall annex territory for such a project. In the present case, however, approximately 37 of the 43 acres selected for the site lie in the city. The county territory consists of a strip approximately 150 feet wide by 1,200 feet long that is entirely surrounded by the city and divides the site into two separate and approximately equal parts. It is entirely uninhabited and unimproved. Unless this island, which is an integral part of the site, is annexed, the project cannot be built. Thus the purpose of annexation is not to develop a project outside of the city, but to make possible a project within the city in accordance with the slum-clearance and low-rent housing objectives contemplated by the housing legislation. The questions presented, therefore, are whether the city has contracted or legally can contract to annex such territory as is necessary for the development of a project within its limits.
The authority has the power to “Make and execute contracts and other instruments necessary or convenient to the exercise of its powers” (Health & Saf. Code, § 34311), and the city has authority to “Do any and all things, necessary or convenient, to aid and cooperate in the planning, undertaking, construction, or operation of” a housing project. (Health & Saf. Code, § 34516.)' Pursuant to this provision the city agreed “to cooperate with the Authority . . . by such other lawful action or ways as the Authority may find necessary in connection with the development and construction of the Projects.” Before this controversy arose, these provisions of the housing acts were consistently interpreted by those charged with their administration and interpretation as authorizing the necessary annexation proceedings under the quoted contract provision.
The consistent course of conduct followed by the city before it attempted to abrogate the entire housing program makes clear that it agreed to annex the county island as a necessary step in the development of a project located in the city. (Woodbine v. Van Horn, 29 Cal.2d 95, 104 [173 P.2d 17]; Davenport v. Davenport Foundation, 36 Cal.2d 67, 73-74 *687[222 P.2d 11].) That course of conduct, however, amounted to more than a practical construction of the contract between the parties; it also constituted an interpretation of the statutes upon which the contract was based. “ ‘ [T]he contemporaneous administrative construction of the enactment by those charged with its enforcement and interpretation is entitled to great weight, and courts generally will not depart from such interpretation unless it is clearly erroneous or unauthorized.’ (Coca-Cola Co. v. State Board of Equalization, 25 Cal.2d 918, 921 [156 P.2d 1] ....)” (Richfield Oil Corp. v. Crawford, 39 Cal.2d 729, 736 [249 P.2d 600].)
We have concluded that the interpretation heretofore placed upon the statutes and contract by the parties is correct. The authority is not attempting to expand its territorial jurisdiction by developing a project outside of the city. It is seeking only to effectuate its purposes within the city. As pointed out by the city planning department, “Annexation, as proposed, would permit the consolidation of the housing program entirely within the limits of the City of Los Angeles, absorb an island which is presently located within the County of Los Angeles, surrounded entirely by the City limits of Los Angeles, and permit the construction of the necessary sewers to serve the residences within the proposed housing development which cannot be constructed if the narrow strip of County land is not annexed to the City of Los Angeles. ...”
It is now settled that the city has no right to abrogate the contract here involved or to withdraw its approval of the development and construction of these projects. ‘ ‘ [H] aving taken the initial discretionary action to bring the housing authority into operation and having approved a project and entered into a cooperation agreement, there was nothing left to be done by either contracting party but to perform administratively whatever was necessary to carry the agreement into effect. . . . [T]he law enjoins upon the city the duty to perform the terms of its agreements entered into with the housing authority and to go forward with the exercise of the powers which it has agreed to undertake in cooperating with that authority.” (Housing Authority v. City of Los Angeles, 38 Cal.2d 853, 862, 871 [243 P.2d 515].)
There is nothing in the statutes governing the territorial jurisdiction of the city and the authority that permits the city to evade its duty pro tanto by departing from *688its established policy of annexing unincorporated islands. The authority selected, and the city council approved, a site selected in the city. To develop a project on that site it is admittedly necessary that the county island be annexed. Both the city and the authority have power to do what is necessary to develop projects in the city, and the city has contracted to exercise such power when requested by the authority to do so.
Since the question of annexation was not specifically presented in the mandate proceeding, we are of the opinion that respondents should not be fined for contempt. Petitioner seeks no more at this time than to have respondents ordered to complete annexation of the county island. We may make such an order under section 1097 of the Code of Civil Procedure.
Respondents are ordered to comply with the writ of mandate heretofore issued by annexing the territory in question.
Gibson, C. J., and Spence, J., concurred.