London -- The University of Cambridge's plan for a major expansion -- one of the most ambitious in its 800-year history -- won approval this week from the Cambridge City Council, an important step in a process the British university has said is critical to its future.

The plan, which has been under discussion with local residents and businesses for three years, encompasses 140 acres of suburban land in the northwestern part of the city.

If the project goes ahead as planned, three new colleges would be built, adding to the university's current total of 31. The new site would include housing for students and professors, research and development facilities, recreational park space, a primary school, and shops. The high price of housing in the area has been cited as one obstacle to luring professors to the university, and the plan would include enough new housing to accommodate twice the current number of faculty members there.

The historic heart of the university is in Cambridge's city center, but a rapidly expanding student body has increasingly cramped its urban facilities. Like other British universities, Cambridge has been hit hard by cuts in government subsidies. The university is hoping to capitalize on its strong reputation by drawing more fee-paying international graduate students. Over the next 20 years Cambridge expects to expand its 16,500-student enrollment by 5,000.

The university insists that the expansion is necessary for it to maintain its global competitiveness. A statement posted on the university's Web site says that "in order for the university to remain a world-class education and research establishment, we need to retain the option to develop."

Many details of the university's proposal remain to be worked out, and, according to the statement, preparation of the site's master plan will not begin until this autumn. The land is already owned by the university but is now used primarily for agriculture. Much of it falls in a designated "Green Belt," an area of environmentally protected land subject to rigorous zoning provisions, that surrounds the city.

The proposed development is also near a technology park where several high-technology firms are clustered. University officials have argued that the plan would foster mutually beneficial ties between the companies and the university.

But local environmental activists are expected to oppose the plan on the grounds that it violates the intent of the Green Belt designation.