It’s a pretty impressive CV: 16 years teaching, spells as both head of department and head of year, a secondment to help a neighbouring school out of special measures - surely the sort of stuff of which school leaders are made.

Or so Roy Watson-Davis thought. In the past three years he has applied for 20 assistant head posts and had just one interview, which was unsuccessful.

Roy is convinced his application itself isn’t at fault - he’s had it checked and commended by people he knows and those he doesn’t. But what he finds striking is that not one of those 19 schools even asked to see his references before discarding him. Among the myriad of possible reasons, a nagging doubt remains. What if, at 44, he is considered just too old to get on the first rung of the leadership ladder?

Figures out this week back up his hunch. While the latest school workforce survey shows that about a third of deputy and assistant heads in English secondary schools are under 45, research by Education Data Surveys paints a different picture when you look at the age of first appointment to assistant head, often the entry point to the school management team. Out of 150 assistant head vacancies in 2007-08 in English and Welsh secondary schools, 71 per cent went to candidates who were under 40. For teachers of 45 and over the message is even clearer: 87 per cent of new assistant heads are 44 and under. It’s a similar story in primary schools: 72 per cent of assistant head jobs went to people under 40; 85 per cent to under 45s.

For Roy, an Advanced Skills Teacher at Blackfen School for Girls in Sidcup, Kent, this means that as every year passes his chances of ever getting promotion will diminish. “I don’t expect jobs to fall into my lap, but I don’t understand why my references aren’t even being called.”

He has asked for feedback on his applications, but most schools don’t reply. No one mentions age - not least because it would be illegal to exclude him on those grounds - but Roy suspects it has played at least some role. “I don’t know whether it’s subconscious or deliberate, but age must have something to do with it.”

John Howson, of Education Data Surveys and visiting professor of education at Oxford Brookes University, believes Roy is right to be suspicious. “It does seem that if you haven’t made it by 45, then your chances are slim.” John says that more research is needed into career trajectories to get a clearer picture of why over 45s are under-represented, but there is little doubt the trend is there.

“It is difficult to know to what extent there is a push-pull factor, whether it is mainly people in that age group (under 45s) who are applying, or whether older candidates are at a disadvantage.”

Age discrimination was made illegal two years ago (see panel on page 19), and earlier this month, in one of the few cases to have been brought under the legislation, Milton Keynes Council was found guilty of discrimination against a 61-year-old teacher, after advertising for a teacher “in the first five years of their career”. The council failed to show that their decision to try and recruit a less experienced candidate was justified on the basis of cost, and will have to pay the teacher an as-yet-undecided sum in compensation.

The trend has implications for teachers in core subjects, who may find it takes longer to get to head of department level and be in a position to tilt for the next rung, and in schools where there is less movement at the top. Anything that means it takes longer to move up the ladder may curtail their ambitions. Conversely, teachers in smaller departments or in challenging schools may find there is an accelerated path to promotion, if they want it.

It also has implications for late entrants to teaching or for those who took a career break, either to start a family or for work-life balance reasons.

About a third of all trainee teachers in England are over 30, and for them there is no time to waste. “If you come in over 30 and want to be a head, you can’t hang about,” says John. “Someone who has had a career break or who arrived in the profession later may have exactly the right skills, but may be overlooked because they’re seen as too old.”

While there’s no call for despair - after all, almost a third of new assistant heads in secondary are over 40 - John suggests that schools are potentially denying themselves access to a substantial pool of talent. “There could be a lot of frustration among teachers in their early 40s who’ve got 20 years of teaching ahead of them and could get stuck at head of department level.”

This is bad news for Jeremy Finch. At 41, he is enrolled on a secondary maths PGCE at Oxford Brookes University, due to graduate next summer. A former managing director of a recruitment company, he switched careers to fulfil an ambition he has had since university.

“I want to teach, and once I’ve done that for a few years I’ll worry about what to do next,” he says. “But to be told that you can forget progression because you’re too old is very limiting.”

Jeremy saw age discrimination in action during his recruitment career, although he says it was more common in the private than the public sector. “There are stereotypes associated with youth: that you are enthusiastic and dynamic, and also more easily moulded and manipulated.

“There’s also an attitude that if you haven’t made it by a certain age there is something wrong with you.” Jeremy suggests some managers are uncomfortable with a subordinate who is older or of a similar age, while others look to recruit in their own image.

But while there will always be people with their own prejudices, Jeremy warns that weighing age as a factor at a time when schools are facing a shortage of heads is short-sighted. “To write off a group of people and say they’re past it is a huge waste of talent.”

Andy Brown, a primary head and national succession consultant for the National College for School Leadership, thinks that 10 to 13 years as a classroom teacher is a rough minimum for going into school management, although he adds the rider: “I have seen people with less experience doing a good job.”

He says younger teachers are less likely to have started a family and so may be able to devote more time to their careers, and also may be more ambitious. But Andy, head of West View Primary in Hartlepool, says schools would be missing out if age was a factor in promotion. “We need experience in the profession.”

Some of the imbalance among assistant heads may be down to demographics: about half of all teachers are under 40, with a further bulge among the over 50s. The 40-49 range is relatively under-represented, the consequence of recruitment trends in the Eighties.

A further possibility is that the third of new assistant heads over 40 broadly matches the third of teachers who entered the profession at 30- plus. After 10 years, according to Andy’s guide, these late entrants could be in a position to apply for a leadership post.

Jane Lees, president of the Association of School and College Leaders, says career changers have a lot to offer, bringing skills and knowledge into education from other professions, but suggests ambition should be tempered with realism. “It would be naive to think you can parachute into a leadership position. But if you learn quickly it is possible to progress quickly.”

Jane, head of Hindley High near Wigan, says it would be wrong to equate youth with dynamism and energy, but concedes that stereotypes do give younger teachers some advantages, to counter their lack of experience. “Yes, the youngster is coming into the role with fresh eyes, and they might be seen as being closer to youth culture, although I have older members of staff who the children totally respect.”

Of course, teachers who have got to their 40s without moving into management may simply have decided that it is not for them. A survey carried out for the NCSL last year found that 77 per cent of teachers in the 45-54 age range had no aspirations to be a headteacher, compared with 60 per cent of the 30-44 bracket. But figures for enrolments on the National Professional Qualification for Headship suggest there is still plenty of ambition among older teachers. Of the 2,196 teachers who started the course in September last year, 55 per cent were over 40, well above the proportion (29 per cent) of that age group who moved into leadership. Over 45s make up 36 per cent of the NPQH cohort, but only 13 per cent of new assistant heads in secondaries.

So who’s filling these senior positions? At the other end of the spectrum there are a growing number of teachers joining the leadership team at a relatively young age. Three per cent of deputy and assistant heads in primaries, and one per cent in secondaries, are under 30, according to the EDS survey.

Earlier this month Mark Lewis started as assistant head at Marshland High in West Walton, Cambridgeshire, at the age of 26. Mark, who has since turned 27, is in his fifth year of teaching, having joined the Fast Track accelerated leadership scheme. Ironically, the scheme is now being phased out.

Mark became a head of year at the end of his first year of teaching and key stage 4 progress co-ordinator the following year. Last year he was named Outstanding New Teacher of the Year for the East of England in the Teaching Awards. His current post was the result of his first interview for an assistant head position.

“I’ve been very lucky in the opportunities I’ve had and in the people who have mentored and coached me,” he says. He is aware that being a youthful member of a leadership team can bring its problems, but says he is ready for them.

Ivan Robertson, professor of organisational psychology at Leeds University business school and managing director of workplace psychologists Robertson Cooper, suggests that it is career trajectory rather than age that is the important factor.

“There is a view that if they haven’t made it by a certain age, why not? There must be something about them holding them back, whether it’s motivation or a personality quirk,” he says. “It is a much safer option to go for someone who is going at the pace you expect.”

While that may be some comfort to ambitious career changers, it doesn’t cut much ice with Tom Johnson. In the past three years, Tom says he has applied for 20 assistant head posts and had eight interviews. All have been unsuccessful, but after a while he started to notice a trend: at 42 he was one of the oldest candidates. “I thought I was still relatively young to be applying, but I was surprised at how young the others were.”

Tom qualified as a teacher at 27 and was head of geography before becoming head of humanities at Emrys Ap Iwan School in Clwyd, north Wales, at 37. It was only after a couple of years as head of faculty that he felt he was in a position to go for a management post, but now he fears he may never get there.

“I thought I had to have a body of knowledge and experience behind me, but I may have left it too late. I didn’t expect people to be going for leadership posts in their early 30s.” As a teacher in Wales, he says he has found it harder than his English counterparts to get funding for leadership courses, potentially putting him at a disadvantage. Although he is still optimistic he will get interviews, he is aware that time is running out.

Tom says he’s realistic enough to think that after eight interviews maybe he just isn’t right for school leadership. But there’s a suspicion that it’s not just his ability that’s under scrutiny. “I’d like to think I’ve got something to contribute, but it seems like I’ve missed the boat.”

`AGE AND EXPERIENCE SHOULDN’T BE A BARRIER’

Sally Crowe puts her rapid progress up the career ladder down to exploiting her opportunities. She became an Advanced Skills Teacher four years after qualifying, then head of year, subject co-ordinator and best practice manager, responsible for managing five members of staff.

She turned 29 earlier this month, nine days after starting her first job as a deputy head, in her seventh year of teaching. “I’ve been lucky that I’ve been given a lot of opportunities early in my career.”

Sally, who this summer left Latchmere School in Kingston-upon-Thames to join Green Lane Primary in Worcester Park, Surrey, recognises that her lack of experience could be seen as a drawback, but believes there are advantages to early promotion.

“If you haven’t come across certain pitfalls and knockbacks, you don’t have that dent to your confidence and you still have that `I can change the world’ mentality,” she says.

“You have to have self-belief to push yourself forward and take advantage of your opportunities, and if there is something you can offer, then age and experience shouldn’t be a barrier to that.”

AGE DISCRIMINATION: THE LAW

Discrimination on the grounds of age was made illegal only two years ago. Under the Employment Equality (Age) Regulations 2006, all employment practices are required to be based on skills and competencies, rather than age.

The regulations differentiate between direct discrimination, where someone is passed over for a job on age grounds, for example, and indirect discrimination, which covers job adverts that list a minimum length of experience, or an application procedure that includes tests favouring older or younger candidates, such as fitness tests.

There are circumstances where age discrimination may be lawful, if the employer provides an “objective justification”, such as an employee’s safety, or legitimate economic factors.