Teenagers have won congratulations for their A-level results, amid concerns about the future of the education system.
Students' achievements are being undermined by talk of grade inflation, while a lack of university places will leave many facing "heartache", union leaders claimed.
Christine Blower, general secretary of the National Union of Teachers (NUT) said: "These results are a real testament to the commitment and hard work of young people and their teachers. The Government should recognise this rather than continually undermining such achievement with talk of grade inflation and dumbed-down qualifications."
She added: "Politically motivated tinkering with qualifications in recent years has been damaging rather than beneficial. A-levels and similar qualifications serve a range of purposes for different learners.
"Our future qualification system needs to be well considered and planned, and have wide professional support. Any discussion about reform, whether by Government, awarding bodies, or others needs to include all and this would, of course, include teachers who have a stake in the education of young people."
Sally Hunt, general secretary of the University and College Union (UCU) estimated that more than 120,000 applicants could miss out on a university place this year.
"On the day we should be celebrating the achievements of our young people, the Government's failure to fund sufficient university places means thousands will be left disappointed," she said. "By restricting numbers and making access to university more expensive, the Government is effectively closing the door on a generation of young people who have been told all their lives to aspire to university."
University groups welcomed the results, saying students should be "incredibly proud" of their achievements, with Dr Wendy Piatt, director-general of the Russell Group, saying: "This is the first year that student number controls have been lifted for those students getting AAB or above and even now it is too early to tell how the new approach will affect the final numbers of students entering any individual university or any particular course."
Neil Bentley, CBI deputy director-general, said: "A-levels are the academic peak of the schools system and they are an invaluable benchmark for employers when recruiting. With more employers looking to hire at 18 - often through innovative 'learn-while-you-earn' schemes - the Government should listen to business views to ensure exam reforms help better prepare young people for work and life."
Schools Minister Nick Gibb said: "I am delighted that so many young people have secured good A-level results today. It is always a pleasure to be able to celebrate academic excellence, to highlight the successes of public servants and to underline how impressive so many of today's young people really are."