The exam season may be in full swing but the row about whether or not A-levels will be swept away — even in the teeth of ministers’ objections — shows no sign of dying down.

Across the country, head teachers, from those running top private schools to those in charge of inner-city colleges, are putting together alternative courses, some along the lines of the new school diploma rejected by Ruth Kelly, the education secretary, shortly before the election. She is now under pressure to change her mind or preside over the growth of a confusing hotchpotch of qualifications.

In recent weeks her own officials have indicated that the groundswell of change may yet see “A-levels out the door and the diploma taking over” within a decade — as predicted earlier this month by Ken Boston, chief executive of the government’s examinations watchdog, the Qualifications and Curriculum Authority (QCA).

Last week the chief inspector of schools in England and Wales, David Bell, added his voice to the debate, saying that schools were already doing “more of the things” envisaged for the proposed diploma.

In the face of such developments you might expect the man who spent two years working on the new exam to be a little smug. Last week, however, Mike Tomlinson, a former chief inspector of schools was as sanguine as ever. His diploma — at four levels of difficulty — would have replaced GCSEs, A-levels and vocational qualifications. Instead 14 to 19-year-olds would mix and match a much wider range of practical and academic courses to be counted towards the final qualification.

Does he too think that a diploma will still replace A-levels and GCSEs within a decade? “I think we will move in the direction of a diploma, yes,” he says. “What bothers me is that it is happening willy-nilly and that may cause confusion among students and parents.”

A group of private school heads is in talks with the Oxford and Cambridge exam board (OCR) about the possibility of creating a tough new exam for 18-year-olds. “They say the current system does not give their students what they want,” confirmed an OCR spokesman this week.

Other fee-paying schools have switched to the international baccalaureate, a single qualification that covers six subjects, as a way of raising standards. And Anthony Seldon, incoming head of Wellington college, is convening a series of meetings of university and school heads to discuss what is wrong with A-levels. Behind such moves is a widespread belief that the exam is too easy to allow top universities to pick out high-flyers.

At the other end of the scale,inner-city colleges in London such as Newham and Lewisham are introducing a mix of courses in a bid to enthuse older teenagers switched off by the prospect of A-levels. In Britain, one in four children leaves school at 16, one of the highest drop-out rates of any large industrialised country. “It is pretty poor,” says Tomlinson.

Even down in Cornwall, says Tomlinson, change is afoot. There heads are discussing the introduction of a Cornish baccalaureate.

So if there is such widespread support for his diploma — why didn’t ministers agree? “The change of secretary of state did not help,” he says.

Although Charles Clarke, Ruth Kelly’s predecessor, was replaced shortly before Tomlinson presented his final proposals, Tomlinson reveals that both Clarke and David Miliband, the education minister, had encouraged him to work towards a major shake-up of the exam system.

“Up to that point the system had been subject to piecemeal changes and that had not worked . . . Right up to publication of the report I had been encouraged by both the then secretary of state and his minister to be radical,” says Tomlinson Why did Kelly demur? Tomlinson does not know but says: “Two weeks ago in an interview Estelle Morris (who was education secretary before Clarke) said that it was difficult for any secretary of state to be remembered as the secretary of state who got rid of A-levels.”

So what next? In 2008, Tomlinson says, Kelly has promised another review. But at the moment she shows no sign of changing her mind. Last week a spokesman for her department said firmly: “A-levels are staying.”

Educationists have a track record of getting their way despite the objections of politicians. But there are some who think that Ruth Kelly is right.

Chris Woodhead is another former chief inspector of schools. He is unequivocal: “Tomlinson’s diploma is not the answer.” Instead he says “dumbed down” A-levels need to be made more difficult and urgently.

He warns that both Tony Blair and Ruth Kelly need to get a “grip on what is a dangerous situation”. And, he adds, the officials who are speaking out should take stock. “Either the chief inspector of schools or the chief executive of the QCA are speaking with the tacit approval of the secretary of state or they are not. If they are not they should be sacked.”

In the meantime it remains to be seen whether Kelly will indeed be remembered, albeit eventually, as the minister who scrapped A-levels. With a bit of spin it could even be turned to her advantage. We’ve had “Kelly hours” — the extended hours of 8am to 6pm that state schools are to stay open. What price the Kelly diploma?