Lynden Powell left school at 16 with no qualifications, having failed his GCSEs because he never sat the exams. More than 20 years on, he is on the cusp of becoming a qualified music teacher.
"It's been a tough slog," says the 37-year-old. "For the past few years I've been studying constantly and trying to balance that with my paid work and seeing my wife and two young children. I'm ready for a breather, but I've got no regrets at all."
Mr Powell is part of a growing number of people who return to education - partly through personal ambition and partly because teaching represents a "safer" job within a turbulent employment market.
The number of people searching for teaching courses has increased by 149 per cent over the past year, according to Hotcourses, an online course finder.
However, they have to jump through a number of hoops before they can even enrol in teacher training. A GCSE (or recognised equivalent) in English, maths and one of the sciences are basic requirements for teaching in the primary or secondary sector. A degree is also needed for postgraduate teacher training courses.
For people like Mr Powell - who left school two decades earlier with no qualifications or prospects - it signals years of hard work and determination.
"There were times when I'd had enough, when I was drowning in paperwork and thought, 'there's more to life than this'," he says. "The driving force was the knowledge that one day I'd be doing what I was working towards. Every essay I handed in was a step closer to that."
As a teenager at Cyfarthfa High School in Merthyr Tydfil, Wales, Mr Powell was not a model student. It was only after he left school for a dead-end job that he realised the importance of a good education.
He re-sat his English and art CSEs and then went to college to gain a public services BTEC. He spent the next 19 years in the ambulance service, before deciding it was time for a change.
It took him two years to pass his maths GCSE and has taken him 13 months to complete a part-time PGCE course with the Open University, which he juggled with his job as an ambulance technician and a masters degree in music. His first school placement was back at his old school.
"It was strange to go back," Mr Powell says. "The majority of my old teachers were still there. They adapted to the situation better than I did. It was odd to see things from the other side of the fence."
T revor Jones, his ex-English teacher and school co-ordinator at Cyfarthfa, helped him through it. "As a boy, I remember Mr Jones telling me how disappointed he was in me, how I wasn't reaching my potential and what a fool I was," says Mr Powell.
"Later in life I realised he was right. He saw I could do better even when I couldn't see it myself. He single-handedly lit the spark that led me back to education. I told him to his face and he glowed."
Mr Powell is now applying for jobs. He will continue to do some shift work with the ambulance service until he finds a permanent teaching post. Despite the uncertainty, he still considers his decision to become a teacher the best thing he's ever done.
"I love it to bits," he says. "It's an honour to teach, and a lot of the harder to reach kids seem to really engage with my story."
John and his wife Ruth Bowers also became teachers the hard way. They jacked in their business and sold their flat in order to fund their four-year teaching degree. But first, they had to go back to college to get their GCSEs in English and maths.
"It was a condensed six-month course and it was horrendous," says Mr Bowers. "There was so much work to do and I had such a lack of knowledge. It really was going back to basics."
Mr Bowers is now a maths teacher at one of his placement schools - Walker Technology College in Newcastle-upon-Tyne - something he would have found laughable as a schoolboy.
Both his parents were in the Army, his father as a tank driver and his mother as a cook, and his sole ambition was to join the Royal Marines.
"I had a pretty one-track mind at school and it definitely had nothing to do with education," says Mr Bowers, 41. He gained a handful of CSEs, but none that were equivalent to a grade C at GCSE.
After four and half years in the Marines and a stint in the pub industry, he and his wife set up a tea room and a fish and chip shop in North Shields. When it ceased to be financially viable, the couple sold up and enrolled on a full-time design and technology teaching degree at Sunderland University.
Mr Bowers also squeezed in a 23-hour week at a call centre selling credit cards in the evenings and weekends, while Mrs Bowers worked part-time at a department store.
"We had no financial support apart from our savings and part-time earnings," says Mr Bowers, who also has three children aged two to 18. "We tapped into every hardship fund and student loan going but it often wasn't enough. On one occasion, we couldn't get into Sunderland (to study) because we literally had no money."
Instead of walking the 20 miles from their rented home in Backworth, they eventually managed to hitch a lift with a friend. It paid off when they graduated together in 2005.
"It was very emotional," says Mr Bowers. "I cried and everything. It touches me even now."
Mr Bowers draws on his experience when he teaches pupils. He simplifies his delivery in the classroom - something that he found useful during his own school-based intensive maths training.
Last year, almost 90 per cent of his mixed-ability class gained a grade C or above in their maths GCSE.
"The pupils know I will do everything within my power to get them a grade C," he explains. "I recognise myself in some of them. That care and attention is what I would have wanted."
He is relieved he's no longer self-employed, but knows just how much work is involved in re-training. John Howson, a recruitment analyst, says people without school qualifications have a "long-haul" to become teachers. "Teaching assistant posts are likely to be more sought after," he says.
Going the long way round - by getting GCSEs in adulthood before enrolling in a PGCE or a degree in education - can be exhausting, as Mr Powell and Mr Bowers found.
They are both ready for a good break this summer: Mr Powell will be going on a Mediterranean cruise with his family, and Mr Bowers will compete an Ironman 70.3 triathlon - named after the number of miles he will swim, cycle and run over the course of a single event.
But this is a small feat compared to what he's been through to become a teacher. "My colleagues call me The T100 after the Terminator," he says. After five years of hard study, work and sacrifice, maybe he is.
* The Registered Teacher Programme allows candidates with some limited experience of higher education to qualify as a teacher while still being paid to work in a school. Since 1998, about 1,770 trainees have taken this route. For more information, visit www.tda.gov.ukpartnersrecruitingebrrtp.