The number of universities in the United States offering online degree courses has more than doubled in a year, say researchers.

In the current academic year, 34% of universities provide courses delivered through the internet which lead to degrees - compared with 15% last year.

The rise and rise of the use of the internet in higher education has also seen universities putting much administration online - including application forms, registration and payment systems.

There are also more students with access to the internet in university accommodation - with an estimated third of students now having online access in campus halls of residence compared with a quarter last year.

$2.7bn on campus computers

The national survey, carried out by Market Data Retrieval, estimates that $2.7bn has been spent on equipping campuses with hardware and software - 9% up on last year.

The underlying trend revealed by the survey is for universities to extend beyond their physical boundaries, with the growth in student numbers appearing among those studying for degrees online.

This week saw predictions of an increase in university student numbers in the United States, with the growth driven by more adults returning to learning and the emergence of online degrees which allow students to stay in full-time work.

"What this says is that education no longer solely belongs in the university, and we've seen that coming for some time," said Joani Finney, vice president of the National Center for Public Policy in Higher Education, in San Jose, California.