Admissions officers are facing a weekend scramble to avoid delays in clearing as they grapple with new complexities in the compilation of results.
Tony Higgins, chief executive of the Universities and Colleges Admissions Service, said that some exam boards had reported that a number of schools had yet to deliver all necessary coursework results. Some universities have also reported technical difficulties with the new tariff system.
This year's applicants are the first to come through Curriculum 2000, under which candidates take AS levels at the end of year 12, followed by A2s at the end of year 13.
Cath Orange, academic registrar at Leeds Metropolitan University and chair of the Admissions Practitioners' Group, said: "The results profile is less easy to manipulate through clearing. There have been technical difficulties but all parties have been working hard to overcome them."
Jacqueline Henshaw, head of undergraduate recruitment and admissions at the University of Manchester, said: "We are apprehensive. We have to make sure we don't double count when a student gets an AS level and it is rolled into an A level."
Some 70 per cent of universities are using the new Ucas tariff for the first time this year. The tariff gives numerical values to qualifications and establishes equivalents between different types of qualification.
Lee Martin, head of student inquiry and applicant services at Kingston University, said: "We expressed all our offers in points. The complication will be displacing the results where AS-level results were provided last summer and again this year."
Ian Waghorn, assistant registrar at York St John College, said: "The feeling is that, with bringing this new system on so quickly, there hasn't been enough time.
"The unknown quantity is the increase in applications to old universities and whether they will accept those students - which would lessen the numbers entering clearing."
However, George Turnbull of the Joint Council for General Qualifications, which represents the exam boards, said: "In general, the results will not be late. There are always delays: sometimes it is because people have not sent the appropriate information; sometimes it is because the student comes to an exam that he has not been entered for. There is only so much the boards can do."
Many universities are already advertising clearing places on their websites a week ahead of the official deadline. Hertfordshire University Business School has even launched an online chat room to recruit new students.
* Scotland’s admissions staff are assessing the impact of a rise in the number of candidates who have received “X” grades, to 10 per cent, writes Olga Wojtas. X grades go to candidates who have dropped out of courses, have not completed project work, or whose results have not been submitted by schools and colleges. The admissions officers believe the increase in X grades stems from Scotland’s recently reformed exam system, which includes module-style assessments as well as a final exam, and project-based vocational courses.