The number of applicants accepted on to UK university courses this autumn has fallen, Universities and Colleges Admissions Service (Ucas) figures show.
From September 2006, students pay up to £3,000 a year
The statistics show 389,505 applicants were accepted on full-time courses starting in 2006, compared with 404,668 in 2005 and 375,530 in 2004.
The National Union of Students said the figures were "deeply worrying" in the light of increased tuition fees.
But the government said the overall trend was still upwards.
UK breakdown of results
The total number of English applicants accepted on to UK full-time education courses starting in 2006 fell 4.5% from 301,206 in 2005 to 287,739 this year, the provisional Ucas figures show.
The number of students from Wales accepted on to UK full-time university courses for the same period showed a 0.3% drop from 16,849 to 16,801.
The number of applications from students from Scotland accepted to UK full-time higher education courses declined 3.5% to 26,666 from 27,646.
The figure for Northern Ireland fell 7% from 13,909 to 12,936.
And the breakdown of Ucas figures for subjects showed that some disciplines enjoyed a rise in student numbers this year.
They included chemistry, where acceptances rose by 3.7% to 3,581, social work, up 6.1% to 7,698, and pre-clinical medicine, which rose by 2.5% to 8,011.
This autumn's student intake from England and Northern Ireland is the first to pay increased fees for tuition.
Opponents of the new financial package for students - where they pay up to £3,000 per year for tuition and pay it back after graduation - argue higher fees will put many young people off going to university.
But the government has stood by its decision to introduce top-up fees.
The Higher Education Minister, Bill Rammell, said: "Today's Ucas figures confirm that our opponents are being proved wrong."
Mr Rammell said the figures for England were encouraging taken overall.
"Although this autumn we are seeing a small decrease (4.5%) in university entrants, this comes on the back of a larger than usual increase (8.9%) in those entering last year.
"Compared to 2004, numbers are up by 12,000 or 4.3%. It's as we expected, and is what happened when tuition fees were first introduced in 1998.
"Then, there was a small reduction, after which applications continued upwards. The underlying trend is still up."
But the NUS has called on the government to re-think its "disastrous" policy.
"Today's figures have confirmed our suspicions - that top-up fees are having an effect on some students' choices, deterring some from going to university altogether," said NUS President Gemma Tumelty.
"Our concern now is that what was a bad situation will simply get worse, particularly if the £3,000 cap on fees were to be lifted.
"In that eventuality, an education system could easily be envisaged where some students could afford the best, some would be forced to make do with the rest, and some could afford nothing at all."
The Conservative Minister for Higher Education, Boris Johnson, said: "It is very encouraging that applications are well up on 2004, showing that students still recognise the immense value, intellectually, culturally and financially, that a university education can give them."
But the Liberal Democrat education spokeswoman, Sarah Teather MP said: "The evidence is now undeniable - top-up fees deter people from going to university.
"Ministers must reconsider this mistaken policy that has such a negative impact on young people's futures."