The head of England's most prestigious private school has said he believes that the majority of teachers drift into the profession, and that he is "sceptical" of young trainees who call a life in the classroom their "vocation".
Tony Little, head master of Eton College, admits that he fell into the job after university, believing that it would be a "congenial" thing to do for a short period of time.
His comments have prompted a strong reaction from some teachers, who say that they have had a strong drive to be teachers since their early youth, and from teacher trainers, who say that they see many devoted young recruits.
But Mr Little, who himself attended Eton before studying for a degree at the University of Cambridge and embarking on a career at a number of exclusive private schools, told the recent Sunday Times Festival of Education that a sense of vocation developed only after gaining experience.
"I will be perfectly honest . I represent the majority of people who have gone into teaching," he said. "I drifted into teaching after university as a means to do something that was reasonably congenial for a short period of time.
"There aren't many ways of life where you can be paid for producing a play, reading a few novels, being with some energetic, aspirant people.
"A sense of vocation did come upon me a little later and it's something I'm very passionate about now.
"But I'm also a little sceptical when I come across 23-year-olds who tell me their driven purpose is to be a teacher and connect with the young. I think that's something that more properly comes a little later on."
Mr Little admitted that he had come across many young people who were "extraordinarily good in a classroom in their early twenties". "But it's really when there's more life experience, when they have a better way to put into perspective their own life experience, that they become truly engaged," he added.
Mr Little's comments come amid an ongoing debate about the need for teachers to hold teaching qualifications: free schools and academies in England are able to appoint staff who have not undertaken formal training.
But Andy Jones, dean of the faculty of education at Manchester Metropolitan University and chair elect of the Universities' Council for the Education of Teachers, said that he "didn't share any scepticism for younger teachers' sense of vocation".
He stressed that while there was "much to be said" for experienced people entering teaching, there was also "much to celebrate" about young people with a vocation similar to that of aspiring doctors or lawyers.
He added that Mr Little had overlooked the thousands of people as young as 18 who entered undergraduate training routes: "My view is that the majority of our trainee teachers are young and have always wanted to be teachers," he said.
James Williams, lecturer in science education at the University of Sussex, said that he would not dismiss the idea of young people having a vocation to teach. "What I would do, however, is ensure that the vocational calling is realistic - that the potential teacher understands the reality of teaching, its difficulties and its stresses."
Bernice McCabe, headmistress of North London Collegiate School and co- director of the Prince's Teaching Institute, admitted that a teacher training course was a good way for her to prolong student life. "Not unlike Tony Little, I went into teaching without a strong vocation," she told TES. "I was only 20 when I got my degree, and wanted to spend another year at university. And, of course, there were grants in those days.
"I expect I thought it would be a useful qualification, that I'd teach for a few years and then go off and travel. However, as soon as I was in a classroom with children, I loved it and have never looked back."
Ms McCabe said that young teachers today often showed a "passion and commitment (that) puts my rather half-hearted beginnings in the shade".
"I would say there are some young who do have a real vocation. This generation of young graduates strikes me as being much more focused than mine was," she added.
Abbie Hayden, aged 26, who teaches at Castledown School in Hastings, England, entered teaching straight after university.
"I think with the amount of hours you have to put into the job, you would struggle if you didn't choose it, and you didn't have that strong underlying motivation to do it," she said.