The government should not be held back by an "obsession" about keeping A-levels, says a leading Labour MP.
Sir Mike's exam reform plans are facing a tough political test this week
Barry Sheerman, chair of the House of Commons Education Select Committee, warned the government not to "lose its nerve" over exam reforms.
This week, Education Secretary Ruth Kelly will respond to proposals for a major shake-up of England's secondary school exam system.
Ms Kelly has indicated that A-levels and GCSEs will not be scrapped.
The comments by Mr Sheerman, in an article written for the Guardian newspaper, adds to the calls from education figures urging the government not to water down the reforms proposed by former Ofsted chief, Sir Mike Tomlinson.
'Middle England expects'
With a general election campaign looming, the government seems set to reject proposals for the symbolic removal of A-levels and GCSEs, as part of the introduction of a new four-stage diploma.
Mr Sheerman says: "There are fears that the government will lose its nerve, disregard almost every authoritative voice in education and acquiesce to what it considers to be the will of middle England."
And he says it would be a "tragedy if the government came through with a half-hearted response" by only carrying through the introduction of a vocational diploma.
This week's announcement over the future direction of the secondary school system is described by Mr Sheerman as the "most significant government decision over education" since Tony Blair became prime minister.
But Ms Kelly's comments, reported in Sunday newspapers, have suggested that there will be little ground given over the "gold standard" of A-levels.
"You don't improve a system by getting rid of what's good. I want to improve what we've got, not replace it," Ms Kelly told the Sunday Telegraph.
Key elements of the educational establishment - including the Qualifications and Curriculum Authority (QCA) and Ofsted - have advised the government not to "cherry pick" the Tomlinson plans.
On Monday, college lecturers expressed their opposition to the continued separation of academic and vocational qualifications - which could be the case if A-levels and GCSEs retain their individual status.
They want both types of qualification to come within a single "over-arching" diploma, which will give vocational and academic subjects a greater sense of equal status.
"This is highly likely to reinforce the perception of vocational studies as second class and as a remedial route. This country continues to waste the talents of too many of its young people," said Dan Taubman of the Natfhe college lecturers' union.