The number of students already accepted on to university courses has dropped by almost 7%, official figures show.
As of midnight, a total of 357,915 applicants had had their places confirmed, down from 384,649 at the same point in 2011 - a fall of 6.95%.
The figures, which come on the day that students across England, Wales and Northern Ireland receive their A-level results, also show that around 79,000 UK applicants are still awaiting decisions, and that more than 10,000 people have already applied for places through clearing.
Mary Curnock Cook, chief executive of university admissions service Ucas, said: "More than 300,000 applicants whose places are dependent on their grades are waiting to hear if they have been accepted today.
"Despite the fall in applications this year, entry to higher education remains competitive and we expect to see an active clearing period."
More than 25,000 courses currently have vacancies for UK applicants. Last year, more than 50,000 people got a place at university through clearing.
Ms Curnock Cook went on: "It is important that all students research course requirements thoroughly and think carefully before making a decision that is likely to affect their future career.
"Anyone considering applying again next year can research 2013 courses on our website now."
Universities Minister David Willetts said the number of students going into higher education would be broadly comparable to previous years.
"There is long-term trend for more and more people to aspire to go to university and for more and more employers to look to employ people with higher education qualifications and I personally don't think, taking the long view, that trend has suddenly stopped," he told the BBC Radio 4 Today programme.
"What we are seeing at the moment is there has actually been a slight decline in the number of 18-year-olds - there is a slight shrinkage in the size of that cohort - so what we are doing is we are maintaining university places broadly flat.
"There are going to be about 350,000 places in English universities this year which is comparable to the last few years."
Speaking at the UCAS call centre in Cheltenham Mr Willetts said he was not worried by the 7% drop in the number of students that have been accepted onto their university course compared to the same time last year.
"We'll have to see how things pan out during the day, but my understanding is that we've got almost 300,000 prospective students who have now had their places confirmed and I think that is great progress for this time in the day," he said.
"We will have to see how things develop, but we're optimistic that the system will work in the way that it will and that through clearing perhaps people that haven't necessarily got their university first choice are still able to secure a place."
He also insisted that despite this year's dip in applications the number of 18 year olds applying to go to university was at its second highest level.
"The very big factor (in the drop of applications) is the decline in the number of 18 year olds, because the number of young people is declining because of a fall in the birth rate about 20 years ago.
"When you look behind that, you see that the rate of applications amongst 18 years olds - the crucial group leaving school or college - is its second highest level ever and today here, after all those stories last week about people who weren't applying, I'm afraid the reality today is we are being reminded that getting to university is a competitive process, where there are still more applicants than there are places."
Reacting to fears bright students may miss out on a place at university following changes to the admissions process Mr Willetts said he was confident the clearing process would find places for most students hoping to go to university.
He said: "We will see how the system works out during the day, the clearing system is in place to help people who haven't got the grades that they hoped for and I very much hope that today we will see the UCAS clearing system come into its own and the people who haven't got the grades they were hoping for getting their places in that way."
He added the figures would be analysed by the government and by UCAS but it was too early to say if the changes had affected the number of students getting places at the university of their choice.
"I think that our reforms are going to put more power in the hands of students and of course for those who got AAB or better, now those controls have gone, they can go to the university of their choice, of course subject to the university's own capacity, beyond that it is basically the usual system that we are familiar with clearing there to help people," he added.
Concerns had been raised that changes to university admissions would mean that some students who were predicted to score two As and a B, but just fell short, would struggle to gain a place.
Under a new system, there is now no limit on the numbers of students with two As and a B at A-level that universities can recruit.
But it means universities are likely to have less flexibility to admit students who just miss this standard, as there is still a strict cap on those who score less than AAB.
Cathy Gilbert, Ucas director of customer strategy, said it was too early to say if this was having an effect on the number of teenagers getting into their university of choice and on the clearing process.
"We haven't seen that starting to have an effect," she said.
"I think because today is really about the individual, so it's about the individual student making the right decision for them, irrespective of what is going on across the sector, and that's really where Ucas plays a role today, making sure they have that individual advice and guidance."
The call centre in Cheltenham has around 50 people answering phones between 7am and 7pm along with a team of people answering questions on social media sites. A further 100 trained advisers are based in Liverpool.
Mrs Gilbert said: "The call centre is busy, lots of people have been asking for information and advice now they have got their results.
"What we would say is there's a lot of people who have got the result that they wanted and are going to the university of their choice, and for them real congratulations, they should be going out and celebrating, but there will be people who either haven't got the results they quite wanted or who are wondering whether they made the right choice, so the call centre is taking calls from them to give them advice.
"We're also getting a lot of activity across our social media, a real peak in that this year has been people tweeting their questions to us and lots of hits on ucas.com as well, so lots of different places where people are getting advice from us."
She added that the number of people using social media websites to contact advisers has seen a rise from the same time last year.
"It's a real success story this year, we've worked hard all year on the channels to make sure that we have a range of places were applicants can access us when they need help and advice," Mrs Gilbert said.
"Not everybody wants to pick the phone up and some people have very simple questions that respond really well through Twitter and if it is more complex then we will refer them to the call centre to have a longer conversation.
"The key thing for a student who doesn't quite get the grades they hoped for is don't panic, it's a really important decision and it's really important that they get the right advice at the moment, so they need to really think about the course they want to study on, the sort of university they want to attend and also the sort of career they wanted at the end, so we're here to give them access to that information so they can make that rounded decision today."