There may be constant sniping in the media about education in England, but for many parents in the Far East that’s exactly what they want: an English education. However, they don’t just want their offspring to be taught by any old English-speaking teacher. They want a British English-speaking teacher.

And it’s not just the Far East; England’s teachers are in demand globally. According to provisional ISC Research figures, an estimated 100,000 British teachers were working in English-medium international schools in 2014-15.

“The ideal teachers demanded by all international schools around the world are experienced, skilled teachers whose mother tongue is English,” says Richard Gaskell of ISC Research.

So, internationally, they just can’t get enough of our teachers. Unfortunately, neither can we. We are not producing enough to meet demand here, let alone abroad. The School Workforce Survey for 2014 found 1,030 full-time vacancies in state-funded English schools, compared with 350 in 2011.

That’s despite the fact that state-funded schools have more full-time equivalent teachers than ever before - 454,900 at last count - with primary and special schools feeling the benefit of the increase (at secondary, though, the number of FTE teachers has fallen every year since 2012).

The problem is that the overall rise has not been large enough: targets for new recruits to initial teacher training have now been missed for the third year running. Meanwhile, more teachers than ever are leaving English state schools.

And adding to the pressure is a global teacher shortage. According to Education International and the Unesco Institute for Statistics, we are already 2.7 million teachers short of what we need worldwide and, given the United Nations’ new global goals for education, we will need to recruit 25.8 million school teachers - at primary level alone - by 2030.

It’s a huge problem, but it’s one that should never have been allowed to happen. The National College for Teaching and Leadership had one job: to calculate how many teachers were needed to fulfil demand and recruit the required number of trainees. It failed. Miserably. It seems that teaching is not the only area suffering from a shortage of mathematicians.

There were no surprises to catch them out. The birth rate was going up and once it hit primary, it was obvious, as night follows day, that it would then hit secondary. And with the numbers rising and an improving economy luring graduates away, was it wise to shake up training by introducing School Direct so extensively and so quickly?

The impending cuts may boost overall deficit reduction. But, like trains after a drivers’ strike, any teachers surplus to requirements will be in the wrong places. And we already know how hard it is to get staff to move to areas of need.

Is there a solution? According to many commentators, it is the retention issue that is most pressing. There have been many, many reports of workload issues forcing teachers to quit. But no one actually knows if large numbers of teachers are so disillusioned that they have left the profession completely, gone to the private sector where there is less accountability, or whether they have been lured abroad by sunshine, big salaries and benefits. What we do know is that 49,120 teachers left the maintained sector in 2014, up from 43,440 in 2012, but their destination is unclear because the figures are not broken down.

So where have all the teachers gone? The truth is that no one really knows. But what school leaders know to their cost is that they are certainly not here.

ann.mroz@tesglobal.com