About a quarter of all students in UK higher education may be from overseas by 2025 - double the current proportion, the British Council has predicted.
The change could force institutions to rethink their missions and investment strategies, and might tempt the government to set new targets for the sector to capitalise on the multibillion-pound international market.
The forecast is based on trends and predictions from researchers for IDP Education Australia of "phenomenal" growth in global demand for international higher education.
IDP, whose claims were first published last autumn, has been helping the British Council work out what the implications are for the UK of demand for places growing from 1.8 million international students worldwide to 7.2 million by 2025.
Delegates at a seminar in London on what this might mean for UK institutions heard how the international education market could become so big in future that it might begin to shape government policy and steer universities and colleges in new directions.
That is despite the fact that international education barely gets a mention in the higher education white paper and has failed to feature in education secretary Charles Clarke's debate on the role of universities.
Anthony Bohm, IDP's head of planning and research, told the seminar that the research model factored in per capita income, population trends and higher education participation at home to come up with an international demand forecast for 137 countries.
It found that demand would grow by 5.8 per cent a year up to 2025, with 51 per cent of the world's demand coming from China and India. In Australia, this could mean that the average number of international students in each institution would overtake that of domestic students.
He said: "This demand could outstrip domestic demand. That raises questions about the role of international education."
And he added: "Our industry could go through fundamental shifts from where in the past institutions have driven the agenda for international education, partly through the search for more funding, to a national economic imperative driven by governments."
Not everyone accepts IDP's conclusions. Many have pointed out that even if its predictions are accurate, institutions are highly unlikely to be able to supply the number of places needed.
Geraint Johnes, professor of economics at Lancaster University, who is helping the British Council work out the potential value of the international market, said: "The assumptions in this model take the figures all one way. I would agree with those who have said that the projections are wildly optimistic."
But he added: "It shocks you into realising the system is going to have to make adjustments."
One of the adjustments needed, according to Neil Kemp, the British Council's promotions director, is more investment in international education. He estimates that the UK invests about £150 million a year in international market development while reaping about £2.5 billion in fee income and maintenance costs in return.
He said: "Most of the money needs to be invested by the institutions. They need to develop their programmes in a way that relates to the changing needs."
Mr Kemp predicts that the prime minister's initiative (PMI) to attract overseas students to the UK will take numbers to about 255,000 by 2004-05.
If growth continues at between 4 and 6 per cent a year, the compound increase would take international student numbers to more than 500,000.
He said: "Whether there should be more PMI targets beyond 2004-05 depends on what the government wants to do. One thing seems certain - competition for international students will grow."
The IDP suggests that UK institutions could use its model to decide where they stand in relation to competitors in specific markets around the world.
When considering how attractive their courses are, they should take into account quality, price, reputation and income opportunities for the student in the host country and when returning home.
Another factor governments might potentially be interested in, Mr Bohm argued, was prospects for migration. Developed countries such as Australia and the UK faced an economic challenge as the ageing population grew.
Boosting the labour force through migration of qualified and skilled people could be a solution.
But he admitted that there were possible downsides to the kind of growth in international education IDP was forecasting. Governments in supply countries might object to being drained of their best brains.
Maintaining diversity on the campus could also prove difficult. Tim Westlake, director of the international division at Cardiff University, said institutions would have to carefully weigh up all the pros and cons of international expansion rather than view it simply as a new pot of gold.