England's exams system has lost credibility, a former Government adviser has warned.
Parents and students have lost faith in qualifications, and it will be a real task to win it back, according to Sir Mike Tomlinson.
He also dismissed suggestions of grade inflation in GCSEs, arguing that teaching has improved "dramatically".
Sir Mike is a former Ofsted chief inspector and adviser to the last Labour government, leading an inquiry into the 2002 A-levels fiasco.
Speaking at the Independent Academies Association (IAA) conference in London, Sir Mike said: "This present system, at this point in time, has lost credibility. It's lost credibility and confidence. It's amongst parents, it's amongst students, it's everybody. We have a real task."
Sir Mike suggested that while there is much talk in the UK about grade inflation, other countries have also seen a rise in results.
An international study from 2003 found that among 55 to 64-year-olds in the UK, around 55% had the equivalent to five O-levels at grades A-C, and among 25 to 34-year-olds this had risen to 68%. In France the comparable figures had gone from 46% to 78% and in Australia from 63% to 74%.
"Unless there has been an international conspiracy about grade inflation, which I doubt, I think these figures need a little bit of thought," he said.
"In this country, the quality of teaching has risen dramatically. It annoys me intensely that we don't give credibility for that, and one of the consequences of that is young people working harder, with support from their schools, parents and communities, to achieve as high as possible."
Sir Mike also raised concerns about the Government's plans to reform the education system, warning: "We've had the cart before the horse. We should be starting not with qualifications and accountability, we should be starting with the curriculum in its fullest sense."