One in three 18-year-olds who applied to universities in England, Wales and Northern Ireland this year received several forms of unconditional offers, figures showed, triggering new debates about student recruitment and the effect of separating bids from A-level scores.
A report by the acceptance agency Ucas revealed that open unconditional offers continued to increase this year, from 3,000 in 2013 to 68,000, and reached 87,500 when combined with offers that became unconditional when a student made the university a strong choice.
Combining two forms of unconditional offers means that 34% of 18-year-olds who register through Ucas receive offers from one of the five universities they choose.
Use of controversial unconditional bids among school leaders, who say they interfere with student efforts. But those concerns were only partially borne by the Ucas data, which showed that students holding unconditional offers were slightly less likely to achieve predictable scores than their counterparts with conditional offers.
The numbers show the majority of the sixth form applicants lost the predicted A-level value, regardless of the type of offer held. Applicants with conditional offers to achieve specific grades miss their target with two or more values in 56% of cases, compared to 67% for students with unconditional offers.
Damian Hinds, education secretary, said she found an increase in unconditional offers "disturbing" and warned that universities in the UK could face regulations by the Office for Students for improper use.
"This report shows that many students can be disrupted from their final year of school, and achieve an A-level score that is lower than their ability. This is an effect that we know can have a significant impact on their careers, "Hinds said.
The use of unconditional bidding has ballooned because the government abolished the limit on the number of students entering universities in the UK can recruit, allowing expansion when the number of school graduates declines.
Universities that use unconditional offers say they see some signs that they influence the efforts of their students before or after arriving on campus.
Prof Graham Galbraith, chancellor of Portsmouth's deputy, said: "The Ucas analysis strengthened my belief in the suitability of the Portsmouth University unconditional bidding scheme. We have found that applicants we make unconditional offers are more likely to achieve predictable values than applicants we make on conditional bids. "
To maintain motivation, Portsmouth also provides students with an unconditional £ 1,000 scholarship offer if they reach the predicted A level.
Galbraith said that Ucas's data highlighted serious problems with unreliable A-level predictions used for conditional offers. "If 18-year-olds know that the value of their predictions is no more accurate than a coin toss, is it any wonder that they report that unconditional offers reduce their stress levels and improve their mental well-being?"
Ucas estimated that unconditional offers caused 1,015 18-year-olds to get an A-level of two lower-than-expected classes.
Prof Chris Husbands, vice chancellor of Sheffield Hallam University, said that his agency made hundreds of unconditional offers, from more than 7,000 students recruited this year.
"We don't use them to put homeless people in chairs, in ministerial sentences, we use them to position ourselves at the top of the reach and attract high caliber students. These are students who will enter university, and I want them to come here and not to university on the road, "said the husband.
Sheffield Hallam carefully followed the performance of the students who accepted the offer unconditionally, and found no difference in their achievements or final results.
A survey of 18-year-old children by Ucas found that 70% of applicants supported the use of unconditional offerings, noting: "Many talk about stress reduction, and this mental health and welfare benefits confer."
The University and College Union say controversy shows that the British system for university applications requires radical reforms.
It said: "The time has come for the UK to join the rest of the world and adopt a post-qualification acceptance system, where bidding is based on actual achievements rather than estimated potential."