Universities must not be allowed to squash moves towards a system in which sixth formers would apply for a degree course after A-level results, some vice-chancellors are warning. They are concerned that many of their colleagues will resist change for fear of disrupting the summer holidays or having to alter their campus calendar.

The admissions service, Ucas, reported last week that unconditional university offers rose again this year. This is likely to be met with serious disapproval in Westminster, and accelerate a change in the admissions system.

Controversially, a quarter of students received a so-called “conditional unconditional” offer, meaning they were offered a supposedly no-strings place, but only if they accepted that institution as their firm first choice. The practice has mushroomed as universities fight for students in the fierce new recruitment market. But the former education secretary Damian Hinds said recently institutions that do this are “backing students into a corner”.

The Office for Students, the universities’ regulator, is to launch an inquiry into the admissions process, while Universities UK, the vice-chancellors’ body, has been quick to launch its own review first.

Critics of the current system, in which universities make offers earlier in the year based on predicted grades that are mostly wrong, and where tens of thousands of places are auctioned off at the last minute in clearing, say institutions should switch to post-qualification admissions (PQA). This would make unconditional offers redundant. Despite widespread support for the idea, there is opposition in many universities.

David Green, vice-chancellor of Worcester University, a supporter of such a change, says: “There has long been a highly effective behind-the-scenes lobby stopping the introduction of PQA.”

He adds: “There are powerful forces of inertia to overcome and important practical questions for schools and universities to solve, but there is no doubt: the system must change.”

Many other countries, including Australia, already have a post-results admissions system. Alec Cameron, vice-chancellor of Aston University and formerly deputy head at the University of Western Australia, has been surprised by the opposition in the UK. He says “principled arguments” seem to have been derailed by fears of change.

“Some of the arguments against it derive from a false assumption that students will do their research at the last minute. But in Australia, students make their applications halfway through the school year, although they aren’t processed until they get their results.”

He adds that if Australian students perform better – or worse – in their exams than they expected they can change their choices.

In the UK, meanwhile, the statistics on predicted grades are damning. Three-quarters of students are predicted higher grades than they achieve, and only 16% of grades are predicted accurately, according to University College London’s Institute of Education.

The Sutton Trust has found that the grades of 1,000 top-performing disadvantaged students are under-predicted each year, making them less likely to apply to competitive universities. The charity says teachers are less likely to identify poorer young people as gifted.

James Turner, the Sutton Trust’s CEO, says: “We would like students to apply after they have received their A-level results. This does away with predicted grades and unconditional offers, and empowers students. They can pick the right course at the right university with a high degree of certainty they are making the right choice.”

The idea of applying after results is far from new. A review for the Labour government back in 2004, led by Steven Schwartz, then vice-chancellor of Brunel University, called for the immediate introduction of a post-qualification admissions system. Schwartz concluded that using predicted grades was unfair “since it is based on data which are not reliable, it is not transparent for applicants or institutions, and may present barriers to applicants who lack self confidence”.

University leaders succeeded in burying the plan, arguing that it would involve too much disruption for both universities and schools.

One obstacle is that academics typically use the gap in teaching during the summer to concentrate on research. Under the suggested new system many would instead be immersed in students’ personal statements.

The Universities and Colleges Union, which has been campaigning for a move to PQA since 2015, suggests students should sit A-levels earlier, and universities should push the start of term back to November for first years.

The union says applicants should still research their university choices early in the year, making expressions of interest to up to 12 universities in January. But under its model students would apply in the first week of August, after receiving their A-level results, with universities making offers by the end of September.

Chris Ince, chair of the Association of University Administrators and registrar at London Metropolitan University, says that while there are strong arguments for PQA “the changes that would be required in universities and also in secondary education are really quite challenging. It would need incredibly strong political will to push this through and I doubt whether that is there.”

Nick Hillman, chief executive of the Higher Education Policy Institute thinktank, accepts that a change to the system is fraught with challenges but says the use of “conditional-unconditional” is manipulating students. “This is someone who isn’t even an adult yet making a life-transforming decision, and universities are applying pressure,” he says. “That just doesn’t feel right to me. I want young people to follow their hearts.”

Meanwhile Green, whose daughter is waiting for A-level results next week, says that the predicted grades system is hugely stressful for students and “wholly outdated”. He says: “When results come in next Thursday the newspapers will be full of pictures of delighted students who have got three A*s. But they forget there are people who are deeply anxious because they are so worried about not making their grades.”

Green says many young people start basing their lives around their prospective university long before they go. “A slip in grades can seem like a disaster and lead to trauma, which is all too real.”