This time, the feeling of going back into a teaching job filled me with dread.”

Primary teacher Salma Hamid has taken several career breaks from teaching. But when she was mulling over another return last year, she just couldn’t bring herself to do it. “I see friends who are still in the profession, how run-down they are, how stressed they are,” she says. She ended up taking a job as an MP’s caseworker instead.

Salma’s story is just one piece of the much larger recruitment crisis gripping the English education system.

A Tes analysis last year revealed that the country will need 47,000 more secondary teachers by 2024 to cope with an explosion in pupil numbers, along with 8,000 extra primary teachers. And that doesn’t take into account the teachers leaving the system.

But a solution might be staring schools in the face. According to one estimate, there are 300,000 qualified teachers of working age who are not teaching, and up to a fifth - 60,000 - could be persuaded to come back.

So how can schools ensure that the next Salma makes a different choice, and returns to the classroom? What would the returner teachers who have made it work recommend?

Emma (not her real name - she prefers not to be identified) is a maths teacher who taught for a decade before taking a career break to raise a family.

She returned to the classroom six years later, and says that completing a subject knowledge enhancement course nine months prior to returning was a huge help. “[The] course brought me up to date and gave me the confidence to return,” she says.

Emma’s experience chimes with an evaluation of Return to Teaching - a Department for Education pilot launched in 2015 to encourage qualified teachers to go back to school.

The evaluation by the National Foundation for Educational Research found that a “lack of confidence and recent experience” of the classroom was one of the key barriers for returners, and one of reasons why the scheme did not recruit more people.

But returner teachers are a diverse group, and their needs and preferences will vary widely. Hannah Cusworth, 29, left her job as a history teacher after two years to work in the City, and returned three years later. She says she wouldn’t have wanted a formal reinduction programme. “Everyone is going to be quite different and that’s really difficult then to formulate a mass programme,” she says. “I would have really hated to sit through a returners’ programme, because I don’t think it would have been particularly helpful. It would have felt like the worst form of school CPD, where you’re all sitting in the hall together and you just don’t want to be there.”

Although Cusworth didn’t have a formal reinduction, she did benefit from a soft landing back into teaching. She joined the school in the final half-term and didn’t have to teach a full timetable to begin with. “I had some time to get back into the swing of things, which was super-helpful,” she says.

By far the biggest barrier to returner teachers, though, is the lack of flexible working opportunities in schools.

Lucy Kellaway, who set up the organisation Now Teach to help older professionals in other occupations to switch into teaching, is scornful about schools’ attitudes towards part-time work. Kellaway wrote about management for the Financial Times for 30 years before retraining as a teacher, and she went part-time after her training year. “One of the things that we’re trying to do at Now Teach is to push the part-time agenda,” she told Tes in an interview last year. “I think schools are in the dark ages on part-time working, compared with any other industry you can think of.”

Russell Hobby, chief executive of Teach First - which has just launched its own returner-teacher pilot - agrees. “One of the big reasons people leave teaching is to have a family,” he says. “The very fact that they think they need to leave teaching to have a family should be of concern to us, but coming back they are likely to want different-shaped working practices.”

Flexible working was crucial to Emma’s decision to return to the profession. However, she says she was “lucky” that the school she previously worked at wanted her back. “As maths teachers are hard to find, they were more flexible about my hours than most people experience,” she admits. “I am well aware that I only got this flexibility because my headteacher thought I was worth the hassle of the timetabling issues.”

And, unfortunately, Emma still finds herself fighting tooth and nail to hang on to her flexible working. “Every year since [I returned], I have had to fight for those hours again, and sometimes I only get them because I threaten to leave,” she says. “I shouldn’t have to do this … I love my job but it has to fit around my family.”

The DfE is aware of such problems and last month proposed a “job-share match.com” for teachers. But there is still a long way to go. Both Emma and Hannah Cusworth went back to the classroom and are still there. So the reasons they give for why their return was successful could be an example of survivors’ bias. It is, therefore, crucial to also learn from those whose return didn’t work out quite so well - like Salma Hamid.

Hamid qualified as a primary teacher in Birmingham in 1997. During her career, she has taken several breaks from permanent teaching posts, and made several returns. After the birth of her third child in 2006, she had a four-year career break. When she returned in 2010, she found that it was “really hard to get back into it - so much had changed”.

However, her return was made easier by the fact that, although she was in class five days a week, she was teaching for only three of them. “I was almost like a teaching assistant for those two other days,” she says.

After three years, she decided to do supply teaching to give her more flexibility, but she missed building relationships with children and colleagues, and returned to a permanent post on a part-time basis. But she realised something had changed. “The whole work-life balance wasn’t there as it used to be,” she recalls. “And even though I was only working three days in a school, the workload was such that I might as well have been working five.”

It was the workload and the constant changes to the education system by politicians that made Hamid decide against returning to teaching after her most recent stint out. “I do miss the teaching children aspect of it. I miss the staff. I do not miss the workload,” she says.

Schools can’t do much about the inclination of politicians to tinker with the education system. The power to solve workload might not be completely in their gift either, but anything they can do to lighten the load will help to entice lapsed teachers back to the classroom.

So while the recruitment situation feels bleak, it does seem that the changes that will attract returners back to the profession are the very same changes that will improve retention and encourage more graduates to apply to teaching - improving the working conditions and the standing of the profession.

“Teaching is not going through a good time, media-wise,” reflects Cusworth. “A lot of people don’t see it as a particularly nice place to be at the moment, but there are a lot of really nice schools out there.”

This article first appeared in the Tes magazine issue of 15 February 2019 under the headline: “Can we tempt you back…?”