Sally Rush's journey into teaching was far from linear. As a teenager, she had never been terribly enamoured with school, and higher education was an uphill struggle. She barely managed to scrape a 2:2.
It was not until she decided to embark on a teacher training course that she felt she had found something she really had a knack for. Teaching came naturally to her, and fulfilled her in a way that academia had never done. "I felt I could relate to my pupils in a way that other teachers couldn't," she says. "I firmly believe that my struggle with academia has made me a better teacher."
Under David Cameron's plans to make teaching a "brazenly elitist" occupation, Ms Rush would have had a difficult time making it into the classroom. Under the Conservatives' plans, graduates with third-class degrees and those from some former polytechnics would receive no financial help with their teacher training. Meanwhile, only students who achieve a 2:1 or above in mathematics or a "rigorous science subject from a good university" would be able to apply to have their student loans paid for them.
"Cameron discriminates against those who have achieved a 2:2 and those who went to the new universities . people like me," says Ms Rush. "In my experience, many of the best teachers have done their first degrees as mature students, often through distance learning or at one of the new universities."
It is not only Ms Rush who is affronted by David Cameron's rhetoric - his suggestions have angered teachers who believe their class of degree is no indicator of ability to teach.
According to Linda Hendon*, an advanced skills teacher (AST) from Greater Manchester, it is not always the top academic who makes the best teacher. "I gained a 2:2 in my bachelor degree and went on to become one of the first cohort of ASTs after only five years of teaching," she says. "My teaching practice grades were As and this is a more important indicator of promise as a potential teacher."
Ms Hendon suggests a better way to see if candidates are suited to teaching and the PGCE would be to offer assessed voluntary placements, rather than relying on degree class. "This would serve a greater purpose in determining potential for successful teaching," she says.
Debra Myhill, who teaches at the University of Exeter, says that class of degree is only a small part of the process of selecting candidates for the PGCE. "It is a really complex issue and I suspect it is unwise to legislate too strongly about precise entry thresholds. It has to be a rounded judgment of all of a person's aptitudes, not just a crude diktat about degree class," she says.
Sally Rush agrees. When she dropped out of school at 17, she was convinced she was not bright enough to go to university. She began to work full-time until - nearly a year later - she returned to do a GCSE evening class. She then completed her A-levels over the course of two years, and struggled to keep up.
"I failed one of my A-levels, and came out with awful results on the other two, which meant I ended up at the one institution in the country that would accept me to do a degree," she remembers. "Even then, I only managed to gain a place through clearing."
It was not until Ms Rush enrolled on a PGCE course at Canterbury Christ Church University several years later that she felt she had found her calling. "As it turned out, teaching was something for which I had some natural flair," she says. "Suddenly, I was inspired. I was determined to create a classroom environment that encouraged curiosity, creative and critical thinking, imagination, discipline and a passion for lifelong learning."
For Ms Rush, training as a teacher was an eye-opening experience. She realised that qualities such as patience, creativity and a willingness to go the extra mile were what set her apart as a teacher. "I am convinced that these skills - as well as clear, consistent boundaries - are what make a good or, indeed, outstanding teacher and are far more important than whether you achieved a first-class degree at university," she says.
However, most teachers will agree that academic subject knowledge is equally important. "It is hard to explain concepts or ideas to young learners if you don't have a strong grasp of them," says Miss Myhill. "If trainee teachers have rote learnt or passively learnt their subjects, this shows when they have to explain it to others and answer their questions."
John Tandy, induction and CPD consultant for Teachers TV, suggests that it is doubtful that this is dependent on the class of degree as graduates commonly have sufficiently secure subject knowledge for the aspect of the school curriculum that they teach.
"Great teachers are critical - they don't thirst for `tips for teachers', they engage with the problems in the classroom and try to find solutions," he says. "They are neither passive accepters of policy, in school or nationally, nor are they oppositional, rejecting every change - but create reasoned arguments and positions."
The difficulty is that degree classification is only a partial indicator of that talent. It is not always possible to know whether someone with a 2:1 possesses these qualities, or if someone with a 2:2 does not. In addition, universities vary in the degree classes they award.
Mr Cameron's policy seems to suggest that graduates from "elite" universities, such as those in the Russell Group, which represents 20 of the UK's most prestigious universities, should be regarded more highly than others. "Education policy seems to be that where you studied is more important than what you studied, or how well you did, or how suited you are to teaching," says Stuart McAusland, 26, who graduated with a third in maths from Durham University and completed his PGCE there.
Mr McAusland is deputy head of mathematics at Plantsbrook School in Sutton Coldfield in the West Midlands and was recently selected for a prestigious scheme to fast-track new teachers towards senior leadership positions.
"To suggest there is a correlation between degree class and potential for teaching and that someone with a third-class degree is incapable of doing it is fallacious," he says. "I feel I have got a good rapport with my students and I help them to succeed. I like to think I inspire them to enjoy maths. That is absolutely nothing to do with the level of my degree."
According to Miss Myhill, there may be reasons why someone was awarded a 2:2 or a third which are more about circumstance than academic excellence. "At Exeter, we have tended to take a majority of students who have 2:1 or above, but we have also regularly taken trainees with a 2:2, when other aspects of their application are strong," she says.
If, for example, the applicant has substantial experience of working with young people such as running a theatre company or working as a teaching assistant, this can help their application, she explains. "We find we have students who do not have strong subject knowledge or are not intellectually robust, but this is rarely directly linked to degree class."
One of the aims of raising the bar to get into the profession is to do away with the impression that it is a default career for people who don't know what else to do.
According to David Cameron, Britain can learn from Finland, Singapore and South Korea, which "have some of the best education systems in the world because they have deliberately made teaching a prestige profession". In Singapore, teachers enjoy free training, with a salary or a stipend while at university - and new teachers earn more than new doctors.
"The drive to attract the brightest graduates into teaching is a good one, but we need to leave flexibility for reasonable judgments to be made on an application, based on an applicant's whole profile," says Miss Myhill.
Bob Hope, a former geography teacher at the Kidbrooke School in southeast London, has seen many trainee teachers come and go throughout his 30-year teaching career. "I think that the best teachers are not that bright, but incredibly well organised," he says. "I remember one young trainee who had graduated with first-class honours. After about two months, he said to me: `I can either be an excellent teacher, or I can be efficient, but I can't be both'.
"The whole business of preparation and marking defeated him," says Mr Hope. "Even though he was extremely sharp, the sheer bulk of the task evaded him. If you see teaching as a limited task, then you might well be more efficient at doing it than people who want to reach for the sky."
Similarly, Paul Nialls, who has acted as the professional mentor for trainees at Portsmouth Grammar School since 1998, has seen a number of very well qualified graduate trainees - at least two of whom had further degrees - leave PGCE training courses because they could not cope with the pressures of teaching pupils in the classroom. "Teaching is a profession that requires a complex mixture of skills," he says. "The possession of good subject knowledge alone, without the necessary communication and organisational skills to accompany this will not suffice."
Mr Nialls thinks it unlikely that Mr Cameron's proposals, if implemented, will improve the standards of teaching. Instead, he suggests it might create issues concerning the quality and supply of graduates who wish to enter the profession.
"Recruitment in shortage subjects has been easier this year due to the current economic climate. Excluding those with a 2:2 could seriously affect the numbers applying to PGCE courses and hence, the availability of NQTs in these shortage areas in future," he says.
Sally Rush, now a dedicated teacher, is convinced she would not have made it anywhere near a classroom if she had faced these sorts of barriers. If that had been the case, her pupils would have missed out.
Source for box: www.conservatives.compolicy.aspx * Not her real name
If elected, the conservatives will:
* Not her real name