The Schools Standards Minister has launched a robust defence of A-Levels ahead of the publication of this year's results.
Thursday's publication of A-Level results is expected to see a rise in both the pass rate and the percentage of pupils achieving the higher grades.
Critics claims that the rising pass rate, which stood at 95.4 per cent last year, indicates that the exams are getting easier.
In a speech this morning in London, David Miliband hit out at the critics by saying that standards were rising and that the claim that exams are being downgraded is the "biggest myth in education".
"The Government's fight is on behalf of hard-earned merit not easy prizes. We stand for success based on worth not birth. And we will not be distracted from building wider educational opportunities by those who see a danger in meritocracy."
"I want to put this debate in its proper context. The context of myths about education that mark out this country . myths that stand in the way of the progress for hard-working pupils and families for whom education is a one-off chance to break into the winners' circle; myths that put barriers of birth rather than merit to the rise of hard working pupils from all over the country."
Pointing to improved achievement amongst girls, the lowest socioeconomic groups, and amongst ethnic minorities, Mr Miliband said: "My argument for reform contains within it a challenge to those who make these myths. When the facts say teaching standards are rising; when the facts confirm the rigour of test and exams; when the facts show that the growth in pupils doing well comes from Middle England families; the only conclusion we can draw when commentators talk of 'dumbing down' is that they believe Middle England has neither the brains nor the talent to succeed.
"The answer to rising numbers of A grades is not to shift the goalposts so more people are downgraded, but instead to create new opportunities for the most able young people to distinguish themselves. Vigilance and reform, yes; myth-making, no."
Mr Miliband's comments were warmly welcomed by the main teaching unions as providing a crucial counterpoint to the "annual ritual of denigration", according to NASUTWT.
Its acting general secretary, Chris Keates, said: "I am sure that teachers and pupils will welcome the strong statements to counter the critics made by the Minister for School Standards, David Miliband".
"Critics of the exam system have excelled themselves this year by beginning the annual ritual of denigration of the achievements of pupils and
the hard work of teachers even before the results have been published.
"All the accepted national indicators, including Ofsted, demonstrate that standards are rising but then why let the facts get in the way of a good criticism?"
The Association of Teachers and Lecturers (ATL) deputy general secretary, Gwen Evans, echoed his comments. Ms Evans said: "There are three factors that critics seem to have conveniently forgotten. Students know that only their best will be good enough, so competitive is the environment. Teachers are doing everything in their power to remove barriers to achievement.
"But most important of all, is almost never mentioned. Parents educated to degree level are best placed to support their children's educational aspirations - and this generation's parents had the benefit of the university expansion of the '70's.
"Perhaps 2004 will be the year we stop turning a big success into a problem."