Universities face their “busiest” ever period of clearing as a record number of students are due to take up degree places this year through the system, the head of the admissions service has predicted.

School leavers who have had their gap year plans disrupted by Covid-19 will be among those who choose to bypass the main application scheme in favour of searching for a course through clearing, Ucas said.

With less than a week to go until students receive their A-level results, nearly three in four of the UK’s top institutions have vacancies on their undergraduate programmes on the clearing website.

Clare Marchant, Ucas’s chief executive, believes as many as 80,000 applicants could find a place via clearing, up from 73,325 last year, despite fears about the impact of Covid-19 on the student experience.

More than 4,500 courses at the elite Russell Group universities still have spaces for students in England via the clearing process, according to a recent analysis by the PA news agency.

Ms Marchant said it was a “good year” for prospective students in Britain who wanted to attend university in the autumn as institutions will be competing to fill their courses at a time of uncertainty.

The “fragile” situation, where the number of overseas students could fall amid Covid-19, alongside the fact there are fewer 18-year-olds in the population, plays to UK “students’ strengths”, she told PA.

“I think we will end up with significant numbers through clearing,” Ms Marchant said.

“I think it’s going to be probably the busiest yet.”

Clearing has become an increasingly popular route to securing a university place in recent years, in part due to reforms that lifted the cap on the number of students universities could recruit.

It is also used by students who may have changed their mind about their course or university and want to find somewhere new, or those who have done better than expected and want to trade places.

This summer, Ms Marchant expects to see students whose gap year plans have been affected by travel restrictions due to the pandemic – or students who had planned to do year-long internships before starting higher education – also applying directly through clearing for a university place for this autumn.

“I am expecting there to be a number of those,” the Ucas boss said.

“(They’re saying) ‘I’m not going to defer, or I’m going to come in for the very first time’.”

A number of top universities, including Warwick, Bristol and Sheffield, said they have already heard from applicants – who were due to start in 2021 after a gap year – requesting to start the course this autumn instead.

But Ms Marchant admitted that more local lockdowns in the weeks to come could “influence student choice” ahead of enrolment in the autumn, as she added the situation was “exceptionally fragile”.

An analysis, conducted by PA, shows that as of Friday evening, for applicants living in England, there were 29,163 courses with availability across 327 UK universities and colleges.

Seventeen of the 24 Russell Group universities had vacancies on courses for English residents – a total of 4,509 courses between them – on the Ucas clearing site ahead of results day on Thursday.

The Russell Group universities which had the most courses available were Glasgow with 608, Southampton with 378 and Liverpool with 355.

A-level students had their exams cancelled this summer due to Covid-19.

Instead, schools and colleges were asked to submit the grades they thought students would have received if they had sat the exams.

Exam boards have moderated the grades – which students receive on Thursday – to ensure this year’s results are not significantly higher than previous years and the value of students’ grades are not undermined.

Last week, Mike Nicholson, director of student recruitment and admissions at the University of Bath, told Times Higher Education magazine that universities could have less wiggle room this year to admit students who see their predicted A-level results downgraded and who miss out on places.

Student number controls – and a lack of accommodation or classroom space to comply with social distancing – may be barriers to admitting students who fail to meet their offers, Mr Nicholson warned.

Universities in England are only allowed to recruit 5% more UK students than their targets this year to prevent institutions from over-recruiting to make up for lost revenue as a result of Covid-19.

But Nick Hillman, director of the Higher Education Policy Institute (Hepi), believes it is a good time for British students to apply – despite the cap on places and the “controversies over exam results”.

He said: “A big second wave would obviously be a disaster for universities and students but I am clear in my own mind that – if I were 18 this year – I would be planning on going this year, in part because the alternatives are so ropey.

“The biggest challenge for universities, therefore, may not be recruitment but retention after students have arrived on campus.”