The questions were all about the literature of gothic horror, which turned out to be strangely appropriate, because this was the A-level paper that made John Bridges’s hair stand on end.

Staring at him, right there on the computer screen, was the absurd claim that in the final, “synoptic” module of the English literature A-level (an exam that draws together the skills and understanding learned across the course) as many as 14 out of his 15 candidates had been awarded U. The other one escaped with an E. As horror stories go, this was even less plausible than the Edgar Allan Poe studied by his students.

John Bridges is head of English and drama at Wrekin College, a small, fee-paying school in the shadow of the famous wooded slopes of the Wrekin, a strange and dramatic outcrop in the heart of Shropshire.

No one had been expecting congratulations from the Nobel prize committee when the results arrived in August, just the usual spread of grades.

Mr Bridges has been teaching the syllabus for the past 10 years, and is usually fairly accurate in his predictions. “The first thing I thought is that there has been a clerical error,” says Mr Bridges, still baffled almost two months later. “We can’t have got 14 U grades. I started ringing universities, then I started ringing the board, OCR.”

It quickly became clear that something murky was afoot. He got hold of the original grade thresholds “from a lady on the desk” at OCR headquarters and found that the pass mark for the coursework alone had mysteriously risen by 17 percentage points. An explanatory letter from the board confirmed his fears, when Dr Ron McLone admitted that grades had indeed been altered to bring them into line with expectations. This proved to be the revelation that set the national controversy alight.

Although A-level coursework grades have attracted most of the attention so far, many schools, including Wrekin College, are more concerned with the written exam papers, the final “synoptic” module on gothic literature in this case. “Yes, our coursework marks were depressed by a grade or so. But of 15 candidates in the synoptic paper, 14 scored U and 1 scored E, which is crazy,” says Mr Bridges. “We have asked for remarks, of course. A group of us here at the school have tried marking a sample of scripts, which we got back from the board, sticking close to the mark scheme, and we can’t get anything below a D.

“One girl wanted to go to Cardiff to read English literature. She managed to keep her place, thanks to badgering by the school, but she lost her original accommodation. Another chap wanted to read PPE at York, but he is having to take a gap year. Other people who set their hearts on a particular university have had to go through clearing.”

Although it is not fashionable to say so, the bewildering injustice of it all has also undermined the professional confidence of the staff. “I’m in limbo,” admits Mr Bridges. “You feel the rug has been pulled from under you. I have taught the OCR syllabus for 10 years now yet, apparently, I don’t know what I’m doing. That’s not right.

“The students know they have done nothing wrong, and nor have we. As their teacher, I find it hard not to feel that there must be something we can do. But of course there isn’t. You feel helpless, and it undermines your self-belief for a while. It certainly causes you to ask questions. I’m having to teach the same course to the upper sixth now, trying to reassure them.

“I’m still waiting for answers. We’re not looking for a set of As. We’re looking for justice.”

It is a common pursuit. Just a couple of miles south at Much Wenlock, William Brookes school is also in a state of bemused outrage. This time, however, it is a comprehensive that has suffered, and the board taking the blame is the giant Assessment and Qualifications Alliance, not the OCR. “It has affected a limited number of pupils at my school, which has a small sixth form,” says Catherine Cole, head of sixth form and an A-level history teacher of 17 years’ standing. But we have students who got five As in all their other modules, then in the sixth module got a U.”

An A-level drama student saw her coursework downgraded from a C to a U despite the initial agreement of the two exam board moderators who saw her work and her teacher’s mark. A general studies candidate got four As, then a U in the final paper. The same thing happened to a star PE student, this time with the OCR.

Every sixth form in Shropshire believes it has been affected, says Ms Cole, particularly at the AB borderline - as if that had been targeted by the exam boards. Ms Cole believes her AS candidates (taking the first half ofA-level) have also been marked harshly: “My results are way below what we expected. Last year three of our students had 100 per cent. This year the best was a B. Last year the lowest mark was 43 per cent, this year it was 30.

“I’m starting to work with my new Year 13s, trying to buoy them up, tell them it will be OK. They say, ‘You said we’d do really well, and we didn’t’. Then, sitting in front of my Year 12 students I’m starting to ask, ‘Do I know what I’m doing? Can I trust the grade descriptors?’

“As head of sixth form, I have to advise my students and staff on how to predict grades for the UCAS form. It’s very unsettling. Students who have picked up unexpected C grades at AS are now wondering if they can apply to the universities they want.

“I’m happy to believe that it’s the result of incompetence - that the boards had too few markers. We don’t want it to be a conspiracy because, if it is, the whole system crumbles. We’re dealing face to face with students, and we want the system to work. We have vulnerable students in front of us wondering if they’re going to the best universities when they have spent their lives being told that’s where they’re going. I have taught A-level for 17 years and this is the first time I haven’t had an A.”

The school has appealed, but even this has been made difficult. Not only is it an expensive process, but the boards imposed a rule that no school could see its scripts and appeal unless it had asked for the papers by August 23 - only eight days after the results were released, and when most teachers were still on holiday.

Tim Boardman, head of sixth form at Chasetown high school, Staffordshire, is another teacher determined to make clear that the grades fiasco goes well beyond a handful of fee-paying schools and the OCR board. Yet again it was a final written paper in an English literature exam that caused astonishment, this time with the AQA. All of them were marked unclassified - even though Ofsted gave Chasetown’s English teaching a glowing write-up. “We simply can’t understand why they have been given fail grades,” says Mr Boardman. “It’s a big blow. We have been left in the dark about what’s demanded of us. And it’s affected our ability to say to a particular student, ‘Yes, go ahead and apply to that university’.”

Colin Marsh is head of modern languages at Bedford school, one of the oldest public schools, which is this year celebrating its 450th anniversary. His students came to grief with the essay paper for the A-level French course run by AQA.

“Our candidates scored significantly lower marks than in the other two components of the A2 exam (the second half of A-level). And they were lower than in the comparable paper at AS-level, the year before. It’s surprising. Seven out of 10 candidates got a grade U.

“I have been teaching A-level French for 22 years and I have never had an experience of this kind. The low marks in the essay paper are all the more surprising as the skills involved occupy most of your teaching time.” It is not as if his students had read the material just the night before. The set text was a play, Antigone, by the dramatist Anouilh, which many of them had already performed.

“It left me wondering if I’m the right person to predict the candidates’ performance. In one case a predicted A candidate got a U, so we were five grades out. There were other boys whose predictions from us were two, three and four grades out, so there’s a great discrepancy. It’s bound to make you wonder whether or not you’ve interpreted the assessment correctly - although I have no doubt that I did.

“The first thing you see on the computer is the overall grade. After a few minutes, it began to click that the candidates were scoring pretty well on some papers; then the marks dropped. One boy was scoring 100 out of 105, then came up with a mark of 24 out of 90. I didn’t know what to think - just disbelief. The first impulse is to say I have no faith in these results. My candidates have asked for a remark. They are still waiting.

“Most of them have not been badly affected in terms of university applications, apart from one who needed ABB to read medicine at King’s College London. In French he missed a B by one mark out of 600.

“I have been in touch with all my students, asking them if they want a remark. I don’t think their disappointment has come back at me. They feel, with me, that we have all been victims of something weird.”

Across the corridor, his colleague Richard Walker, head of geography, has had a similar disappointment, this time with the coursework option on the OCR A-level, the investigative project.

“It’s been harshly marked in comparison with previous years,” he says. When the results came back they seemed to be at least a grade down on what had been expected. He was particularly surprised because the school had always had plenty of contact with the board and its examiners to discuss what was needed.

“In the past we haven’t had any unclassified grades. But this year, out of 38 we had 10. It was a shock. I had talked to the boys about their particular assignment and suggested ways in which they could improve it. And having been led to believe one thing by me, they feel a bit let down.”

Fourteen years as head of department were made to look meaningless. Mr Walker would normally have looked forward to seven or eight A-grades. This time Bedford picked up no As and 10 Us for the coursework module.

“You can see why I got a bit of a shock from that. One of the difficulties now is setting up the same sort of personal investigative projects for next year’s students - not knowing the standard required.

“I am bemused in the sense that I thought I was reasonably clear about what was required. It looks as though I wasn’t, on the basis of this year’s results. For one lad, I estimated a C and, if things went well, a B. He got a D. I had lunch with him and had to say, I’m sorry, I can’t explain it. I’m concerned because I need to find out the level of work they’re expecting. It has clearly changed.”

A bad set of results can be profoundly unsettling even when the exam board is not at fault. Rose Millard, a history teacher and deputy head of sixth form at Wolverhampton grammar school, was in the unfortunate position of thinking the students taking her AS course with the AQA had been unfairly treated, so disappointing were the marks.

“The AS results were disappointing at a first glance and it became clear very rapidly why. They got the right grades for two of the modules, but Es and Us in the third.” That was British history, the one she was responsible for. “Our gut reaction was that something had gone horribly wrong here - to get As on one paper and Us on the other.”

The school demanded a remark, and the results came back largely unaltered, at which point Ms Millard began to accept that the low marks were probably correct and that she and the students were largely to blame.

There were some other factors, too. “We’re looking at students who had just sat a 90-minute paper on European history. That was then whipped away and they had to start on British, get out of their Weimar mentality and get stuck into Lloyd George. They found that difficult.

“What’s also becoming obvious for AS and A2 exams is that you need to spoon-feed the students loads of information. I feel I failed them because I said, ‘Here are the basic facts, you go and find out more’. We had discussions about the material and they did research, but that’s not enough.” When the chips were down, she says, her candidates had not crammed hard enough, however thoughtful they may have become in the course of her lessons. “I’m fearful that the system is turning out students who have A-grades but no historical understanding.”

She also has concerns about the shortage of markers, which is piling additional pressure and scripts on the dwindling band of those willing to do it. “By the time you get to the 400th script you’re going to be less awake than you were for the first 100.”

But what concerns her most is the feeling that faith in the examination system has been poisoned by the current furore. “What upsets me is looking at students who are worried, not about revising or about taking their exams. They’re worried about who’s doing the marking, and how they’re going to be marked. Sometimes they feel it doesn’t much matter how hard they work because, at the end of the day, someone somewhere is going to do them out of the grade they deserve.”