“I’m one of the highest earners amongst my graduate friends,” says one smart young professional. “In a relatively short time I’ve been able to progress very, very quickly and now I’ve been able to buy my own home, something that I probably wouldn’t have been able to do in another career,” adds another. It sounds like promotional material for a high-powered corporate graduate scheme. But this is actually the government’s latest teacher recruitment advert, as schools face an increasingly uphill battle to attract and retain staff.

Yesterday’s announcement that the 1 per cent cap on public sector pay rises will continue to apply for teachers – despite pressure on Theresa May from some MPs to scrap it all together – will undoubtedly not help recruitment and retention. (Some teachers at the bottom of the pay scale will be eligible for a 2 per cent rise – but schools will have to find the money themselves at a time when they are not exactly awash with cash.)

While things are worse in minority subjects – there has for instance been a 23 per cent drop in trainee physics teachers since 2015 – the situation is worrying across the board. Official figures show more than one in ten teachers quit within a year of qualifying, while a third leave within five.

A survey by the National Union of Teachers found nearly half of those under 35 were considering leaving the profession in the next five years, with most citing workload pressures – and a significant number saying the job was harming their mental health.

“There was a point about five years ago where it seemed like half my social circle were teachers,” says Kai Morgan, who works in post-16 education in South Yorkshire. “Now I hardly know any, and many who I do know don't plan to stick around.” He says the government’s latest advertising campaign, like many others, “seems to put the emphasis on finding another wave of young teachers, rather than addressing the reasons why so many people are leaving in the first place”.

“On the most part, the teachers leaving the job will have been enthusiastic, passionate people hoping to improve people's lives, who felt that their working conditions were preventing them from being able to keep doing this,” he adds. “It's not good for teachers, and definitely not for students, to accept that teachers are just naturally going to be continually 'burnt out' and have to be replaced.

“Yes, it's a rewarding job, but unless working conditions are improved, it's going to keep on being a job that's continuously losing some of its best talent. Putting out adverts emphasising the fact you can earn a good wage isn't the answer to that.”

London teacher Jasmine* describes the promises of sky-high wages to potential new recruits as a “joke”. She says that despite being promoted to second-in-charge of maths she is struggling to get a mortgage big enough to buy a flat. Sam*, another secondary teacher based in the capital, adds: “We have not had a pay rise that's in line with the cost of living for seven years. But no teachers go into the job for the money. It's a vocation, and we do it because we care about education. To suggest that it's worth doing because the money is good is, at best, insulting, and at worst, encouraging the wrong kind of people to enter the career.”

Past teacher recruitment adverts have been accused of promising unrealistic salaries. One in 2008 was even banned, in which a young teacher joked around with a pupil while a voiceover said: “You could earn £34,000 a year. The banter's not bad either.” The Advertising Standards Authority ruled that the teacher’s “very youthful” appearance, among other factors, implied that £34,000 was the starting salary for the newly qualified – which at the time was only £20,000 outside London. Another from 2015, claiming that a “great teacher” could earn £65,000, was cleared by the ASA, which decided that it was evident this was an “aspirational” figure.

The latest advert avoids actual salary figures. But it does appear to attempt to address the profession’s worsening reputation, with one teacher reassuring viewers that, when she started the job, it wasn’t nearly as “horrible” as people had made out.

Complaints about teacher workload are, of course, nothing new. A report by the Commons’ education select committee earlier this year said the government had to do more to tackle the problem – pointing out that frequent changes in policy only added to the administrative burden on teachers. The government’s Workload Challenge, launched in 2014, asked teachers for their views on how to improve things and made recommendations, but was met with scepticism by many in schools.

Alex*, another secondary teacher who is finding the job increasingly difficult, says oppresive accountability is a huge problem: “You’ve got teachers working longer hours, they’re working harder, but they’re actually doing a worse job than maybe they’ve done before because they are under so much pressure to improve what they’re doing, they spend so much time trying to evidence that improvement.

“You spend a lot of time coming up with evidence to prove you’re doing your job properly, and that takes many hours – in that time you could have been planning really good lessons or you could have been marking.”

Many government schemes to address the recruitment crisis have been branded failures. A programme supporting maths and physics teachers who had previously left the profession to return attracted 541 participants – of whom just 63 ended up securing jobs in state schools. Another pilot scheme for returning teachers – which cost the taxpayer more than £500,000 – only brought 49 back into the classroom (its target was 1,000). An evaluation for the first programme blamed schools’ “perceived negativity” about teachers who had left the job.

“Teaching can be such a rewarding profession but it is now increasingly unattractive to new graduates and existing teachers alike,” says Kevin Courtney, general secretary of the NUT. “This is a problem of the government’s own making – it will take action, not [teacher recruitment] videos, to reverse this trend.”

Lucy Kellaway, a Financial Times columnist who co-founded education charity Now Teach last year, thinks the answer could lie in a huge untapped pool of potential teachers who are currently ignored by the government’s marketing. Her organisation is inspired by Teach First – but instead of targeting graduates straight out of university, it is designed for those approaching the end of other careers and looking for a change – she describes it as a sort of “Teach Last”.

Kellaway herself will start training as a maths teacher – the charity focuses on shortage subjects – with the first cohort of around 45 recruits in September. “I myself am in my late 50s and I wanted to become a teacher, and there’s nothing legally to stop me,” she says. “But if you go and look at the general Get Into Teaching website all the pictures are of people who are 22. . . It’s really, really not aimed at people like me.

“The average length of time that teachers spend in the profession is about five years, for some it’s terribly short because it's such a demanding job – it’s too knackering. So that means that – I’ll be 58 when I start – I’m no worse a bet than a 22-year-old.”

Kellaway agrees that workload is a huge issue, but thinks older career-changers – many from high-powered fields such as law and banking – may be better equipped to cope than young graduates. “I’m hoping that we’ll be able to manage, and I’ll certainly be able to manage my time a lot better now than I could have when I was 22,” she says. “And also to know when to stop working, too. You can’t work until two in the morning every day and expect to be fresh to start teaching at eight . . . any school that expects that is insane. We might also be less punishing to ourselves. Or have the confidence to say, ‘Look, I’m a trainee, I’m learning. I know that was a poor lesson but I’ve learned this and this to do it better next time.' When I was 22, if I failed at anything I thought my entire being was on the line.”

Kellaway believes an answer to the retention problem would be allowing more teachers to work part-time. “I think that we could be as big as Teach First one day,” she adds. “There is that enormous pool of people out there, but the only way to turn the expressions of interest into people in the classroom is if you allow them to do the whole thing part-time. And I don’t think that just applies to my age bracket – I think it’s also especially teachers with young children. Schools are really, really backward in accepting part-time. That’s something that we are going to push very, very hard.”

If MPs force the government to provide more money for schools – Education Secretary Justine Greening is said to be pushing the Treasury to abandon plans to cut per pupil funding over the coming years – staff may have slightly more room to breathe. But workload has been a problem long before England’s schools were in such a difficult financial place. And teachers, like everyone else, do not have an endless supply of energy and good will.

However, not everyone agrees with those who feel they are being put under intolerable pressure. “There were loads of myths and horror stories that I’d heard and it just isn’t like that,” says the first smiling young recruit in the government's new advert. “We’re all individuals and it’s going to be a different experience for everyone who becomes a teacher – so there is no use in listening to what other people have to moan about, really.”

* Names have been changed