Even more top grades could be awarded to A-level students this summer than last year to compensate for greater disruption to learning, an academic has said.
It has been claimed today that "inflated grades" will become the "new norm", making it more difficult for universities to "select accurately and fairly".
It comes after Tes revealed concerns from sources close to the Department for Education that next week's exam results will reveal a wider gap between state and private school pupils at A level.
Exams 2021: 'Excessive grade inflation' warning
Teachers in England submitted their decisions on this year's grades after drawing on a range of evidence, including mock exams, coursework, and in-class assessments with the help of questions by exam boards.
Professor Alan Smithers, director of the Centre for Education and Employment Research (CEER) at the University of Buckingham, said: "The early signs are that it will be another bumper year for grades, justified as compensation for all the disruption suffered.
"The danger is that the inflated grades, in other words, lower standards, will become the new norm."
Last summer, the fiasco around grading led to thousands of A-level students having their results downgraded from school estimates by a controversial algorithm led process before Ofqual announced a U-turn.
The proportion of A-level entries awarded top grades surged to a record high after grades were allowed to be based on teachers' assessments, if they were higher than the moderated grades they had received.
Ahead of A-level results day on Tuesday, Professor Smithers warned: "The expansion of the A* and A grades means that a much wider range of abilities is bundled up in them, which makes it much more difficult for universities to select accurately and fairly.
"Some of those admitted may not be able to cope and will have wasted time and money, and some who are much more able will be missing out on when they could have done really well.
"Awarding higher grades in compensation for lost learning can be killing with kindness," he added.
Last year, 38.6 per cent of UK entries were awarded an A or A* grade following the U-turn over grading, compared with 25.5 per cent in 2019, according to statistics published by the Joint Council for Qualifications (JCQ).
Meanwhile, the proportion of entries in England, Wales and Northern Ireland awarded the top A* grade in 2020 surged to 14.4 per cent, compared with 7.8 per cent the year before.
Professor Smithers added: "While logically there is no reason why A-level standards should not be restored to what they were in 2019, my fear is that the various pressures will cause the government to allow what they became in 2020 to stand.
"At best, the grade pattern may fall somewhere between those of 2019 and 2020, but there are hints that there could be more top grades even than in 2020."
He acknowledged that arguments for more sympathetic grading could be made for this cohort as they have faced "disruption in both years of their courses", whereas the 2020 cohort suffered in only one.
Professor Smithers added: "It could be argued that this year's candidates will be competing for university places with the overspill from 2020, and reverting to the harder-edged 2019 grade pattern would leave them in danger of being squeezed out."
"It is also the case that many parents and pupils are happy with the more plentiful A grades because it makes for more room at the top and improves their chance of a place at a top university," he said.
But the report warns that further grade "inflation" makes it difficult for leading universities "to tell applicants apart with sufficient clarity".
It comes after university admissions body Ucas predicted that a record number of students are set to start university and college this autumn with applications and offers up.
Among UK 18-year-olds, the number of applications to higher education has increased by 12 per cent and the number of offers is also up 10 per cent.
A DfE spokesperson said: "Speculation like this is unfair on the thousands of students who have worked incredibly hard over what has been a very challenging 18 months due to the pandemic – and who next week will be walking away with high-quality qualifications that will take them on to the next stage of their lives.
"Exams are the best form of assessment but in the absence of those this year, there is no one better placed to judge young people's abilities than their teachers, who see them day-in-day-out.
"Teachers have assessed multiple pieces of work, in turn giving students multiple opportunities to show what they know and can do.
"As in previous years, the government has been working closely with universities ahead of results day to ensure as many students as possible can progress if they get the grades they need."