There's a teacher shortage coming. It's been coming for a while, but was staved off slightly by the pandemic. Now, it's heaving back into view and the sight isn't pretty.

The first thing to say is that retention also matters. But teachers have always left the profession at fairly high rates in their first few years in the job. And the government really is trying to deal with this via the new Early Career support deal. They may not succeed, but they are trying.

Furthermore, given the likely coming recession, we probably aren't going to see lots of teachers junking their jobs. Hence, while it would be good to keep more people in teaching, that's for a separate article.

The real-and-pressing issue is that we may not be able to hire enough teachers into the profession in the first place.

As Sam Freedman wrote in TES this week, the teacher trainee recruitment figures are grim:

• Only 15% of physics teachers are likely to be hired

• Every subject bar drama, PE, history & classics will miss their targets too

• We are down 10% on 2019, and that was a tough year.

Sam goes on to mention pay and he's right; teaching is not particularly competitive for new graduates. The government is therefore hiking starting salaries to £30k.

But even this may not solve our woes. Plus it definitely isn't going to deal with the gaping non-teaching staff shortage that schools are also facing down.

The truth is that we have some big non-education issues affecting school recruitment that no one is really talking about.

Let me change that now.

1. There are weirdly few 21-year-olds

England is at the nadir of a baby bust. In the year 2000s, for reasons I haven't yet figured out very few people were having children.

In the year 2000, only around 670,000 children were born. The only time in the UK's history where it was lower was 1977. By 2012 it was back up to 807,000. (It is now 715,000).

Not only is this bad news because of the low number of young adults coming into the labour market, it also means the number of children in schools - and especially about to enter primary schools - is very large.

That is doubly bad. At the precise moment when we need more secondary teachers there are fewer people joining the adult workforce.

The only upside is that, in ten years' time, we are likely to have fewer kids in schools and loads of adults entering the workforce. So at least this problem isn't eternal.

2. Graduate employers really want to hire women.

Since 2018 large employers have published their equal pay audits, as required under law. For many companies the results were embarrassing.

A major problem is that many companies didn't hire equal numbers of men and women onto their graduate schemes. Back in 2015 the figures were 60:40 to the men. Add to this imbalance the fact that women historically dropped out of labour markets at higher rate due to childbirth and many companies had heavily male executives. Awks.

So, rightly, graduate recruiters have tried even things up. In a bid to increase diversity, there is an unspoken preference in many places to have slightly more women start in a cohort so that things are more balanced later down the line.

Unfortunately, schools also rely on a female workforce. Last time I looked 85% of primary teachers were female and 62% in secondary schools.

Hence, not only are there fewer young adults in the labour market this year, the big employers - with deep pockets and great work-life incentives - are also coming for the same ones that schools usually recruit.

3. Oh, and the rest of the world wants our teachers too.

Before the pandemic British Schools abroad were growing like knotweed.

Back then the estimate was that international school numbers would double by 2029, increasing the need for teachers from 500,000 (at present) to 916,900. That's almost the entire teaching profession in the UK.

Things slowed a little but those schools will be recruiting again now.

And while teachers in those schools could come from all over the world, British international schools make up 43% of the sector, and there is a premium on native-speaker teachers, which means England's teachers are particularly attractive.

Going to teach abroad is also attractive to many teachers, especially younger ones. Lower taxes and subsidised accommodation makes a big difference to graduates who might otherwise pay sky-high rents, especially in the south of England.

So we have a perfect storm:

• Fewer young adults right when we have lots of pupils

• Graduate employers going after our core market

• International schools also wanting in too

But there's an even BIGGER elephant in the room that we need to address.

One which also affects retention of teachers, as well as non-teaching staff, especially learning support assistants.

The truth is that for the past forever, schools have run off the backs of women who accepted poorly-paid termtime-only jobs because they needed to finish earlier and have school holidays to look after their kids.

That group are now disappearing.

A plethora of work-from-home jobs mean that women who once took minimum wage jobs as teaching assistants can now work flexibly as online sales people, virtual receptionists, social media schedulers, any number of online opportunities all around the world.

They can work while the kids are at school and again when they are in bed. They can log on in the holidays, while their kids are playing Roblox, and keep earning.

Realistically, the ability to work from home in other jobs will also influence some teacher's thinking too. Schools that could rely on being the highest paid graduate job in the area now have to deal with professions becoming remotely available.

However, many teachers come into the job because they love the thrill of the classroom and working with young people - and they are likely to still stay.

For support staff, however, who chose the job because it was the most flexible option available, it's a no-brainer to switch.

Schools are therefore heading into a staffing squeeze, much of which isn't to do with the environment of schools - and it will get worse before it gets better.

What are the solutions? That's for a future blog. But I'd be very happy to hear suggestions and innovations that you've seen or thought of, so please do let me know!