More than 10,000 school leavers who are predicted three Bs in their A-levels this summer have not got a firm offer at any university, as competition for places at top institutions places increases.

Experts say that in recent years school leavers were entering a “buyer’s market” in university places, with applicants standing a good chance of talking their way into a good university even if they missed a grade. But this year, with elite universities fearful of over-recruiting after being forced to take more students than they wanted during the pandemic, and a demographic surge in the number of 18-year-olds, competition has been fierce.

Andrew Hargreaves, founder of Data HE, a consultancy that advises universities on admissions, and a former director at admissions service Ucas, said: “Ucas hasn’t released any official data yet, but I have been told that over 10,000 applicants with predicted grades of BBB are not holding a firm offer at any university. That is really shocking.”

Pupils predicted BBB at A-level are generally regarded as strong university candidates. But with elite Russell Group institutions giving out fewer offers or raising their entry requirements in popular subjects including law, medicine and psychology, Hargreaves said these grades will not have been good enough to net an offer on many top university courses this year. Pupils can apply to five universities, but Hargreaves thinks many BBB students have pitched their choices too high.

“This is a big failure of information and advice,” he said. “We’ve been saying for the past decade that it is a buyer’s market, but the environment has now changed, and Ucas and advisers in schools really need to be stressing that.” Hargreaves said it was fine for students to aim high by applying to “stretching” universities, but they should also have an insurance choice at a university that required lower grades.

He suspects that some 3B students may be “holding out” for clearing in August, hoping they will be able to pick up a last-minute place at a top university. But, he warned: “I think they will be disappointed. I have 12 Russell Group clients and all are telling me they won’t be in clearing.”

Last summer, some selective universities were left scrambling to find bedrooms, seminar space and staff, after thousands of extra students got the high A-level grades they needed to secure their place.

The Ucas chief executive, Clare Marchant, wrote in a blog on Wednesday that the proportion of applications to so-called “higher-tariff” universities resulting in an offer had fallen from 60.5% in 2021 to 55.1% this year.

Prof Colin Riordan, vice-chancellor of Cardiff University, a member of the Russell Group, said: “It’s absolutely clear that this has been a competitive year for applicants. We’ve increased our entry requirements in areas at risk of being oversubscribed.”

He said Cardiff had expanded capacity in some subjects during the pandemic and “we can’t just keep on growing”.

He added: “It is also going to be much more difficult for us this year to help people who miss their offer by a grade, especially in popular subjects.”

Mike Nicholson, deputy head of education services at Cambridge University, said: “Most selective universities have been more cautious as they don’t want to get caught out for a third year in a row.”

Nicholson said that teachers had become used to many universities “saying one thing about what grades they will accept, and then in reality being prepared to drop the grade if they want someone”. He thinks that many don’t realise this has changed at leading universities.

He said: “I don’t blame teachers. They often try to be realistic with students, but ultimately the choice of where to apply rests with applicants who can be influenced by peer or parental views.”

Experts say, though, that disappointed applicants should think hard before deciding to put it all off until next year. Nick Hillman, director of the Higher Education Policy Institute thinktank, said: “If this year’s applicants think they’ve got it tough, next year’s pressure could well be worse, as there will be more 18-year-olds again.”

He added: “Students and parents need to know that there are really good courses throughout the sector, and not just at the most prestigious universities.”