There may be one or two people reading this who dream of exchanging their classroom view of damp school playing fields for the Hollywood screenwriter’s vista of Beverly Hills palm trees. There may be thousands.

For all those readers, take a long, hard look at Philip McGrade. He’s 42.

Tallish. Ginger-ish. Scottish. And your dream come true. Until recently he was teaching full-time at a north London comprehensive. This month his first feature film hits our movie screens.

I’ll Be There is a mainstream English romantic comedy. It might not have laid-off steelworkers taking their clothes off, or Hugh Grant doing his bumbling act, but all the familiar ingredients are there: the jokes, the accents, the tearjerking moments, the inevitable happy ending. The twist to this one is that it is a vehicle written specifically to allow child singer Charlotte Church to make her movie debut as a young Welsh girl (surprise) who wants to be a singer (surprise), but who finds support for her ambition only when fading 1980s rock singer Paul Kerr, played by the Scottish comedian and actor Craig Ferguson, learns she is his daughter.

McGrade co-wrote the film with Ferguson. “Look,” he says, pointing at the video screen in his living room, as if people might doubt it. “There’s my name.” He still seems stunned by his transformation from teacher to screenwriter. “I’ve lived by bells for 15 years. Being free of that is a little trippy. Although there’s a lot of luck involved. I knew the right people at certain points, and that helped.”

But luck was clearly mixed with graft and talent. McGrade studied modern languages at Glasgow University, trained as a teacher at Jordanhill College and worked in Scottish schools for five years.

“When I was 28 I wrote a short story. I only knew one person who was a writer, so I showed it to him, and he happened to be putting an anthology together and it went in there.” From that stemmed readings before audiences and - since the story was “quite funny” - the birth of an ambition to become a stand-up comedian.

“I then had a kind of horrific career in reverse because I got on telly right away (in Halfway to Paradise on Channel 4 in 1990) but it was all downhill from there.”

He moved south and became a supply teacher in south London, battling to teach French and German to tough Forest Hill boys by day while pursuing his stand-up career at night. “At one time they put all the worst classes on one timetable. It was the timetable from hell. There they’d be, throwing chairs around and biting each other, and there you’d be thinking, ‘What the hell have I got into here?’ Although maybe it was partly my fault. I’d be so busy doing stand-up at night, I wouldn’t always remember which audience I was in front of, and I’d be using my heckler put-downs in class. I’d be doing three or four gigs a week, and when you come off stage you’re too wired to go to sleep, so you find yourself sitting up watching The Streets of San Francisco, then the next thing you know the alarm goes off and you’re back in front of 2D.”

When he got together with painter Sarah Stitt, and a baby came along, it was time for a proper job. At Alperton community school, in the London borough of Brent, his responsibilities included running the English language programme for refugee children. By then, breaking through as a stand-up was becoming a fading dream. “Three times I’d given it a big push and it hadn’t happened.” But although he’d never nurtured any great ambition to be a writer, he’d done courses and read books on the subject.

He showed some pieces to a filmwriter friend, who showed them to other people, and out of that came the chance to write an animated film script in Australia.

His wife urged him to go for the writer’s life. “I’d always had one foot in teaching and one foot in show business, and she could see I wasn’t happy.

She had a lot of faith that it would work out, which I didn’t entirely share.” Even so, and despite a second baby on the way, he jumped, and on the very day he resigned from teaching, his old friend Craig Ferguson offered him the to chance to write I’ll Be There. “So part of you thinks, well, maybe it’s my time now.”

Maybe it is. I’ll Be There punches all the right buttons. There are good jokes - “I’m a happy guy,” says Paul Kerr. “I’m rich and I’m Scottish. It doesn’t get much better than that” - and tender moments. Charlotte Church is a competent actress, and there are good performances from Joss Ackland and Jemma Redgrave. In addition, it doesn’t fight shy of being, as McGrade says, “an American’s idea of what a British film should be”, with all the cliches that involves.

So the signs are that it will give filmgoers on both sides of the Atlantic enough of a feel-good experience for McGrade to get plenty more work; he is already writing another script, loosely based on his own life. If nothing comes of it, he’s ready with a fall-back position. “I’ve already asked Alperton if I can come back as a supply teacher.”

I’ll Be There opens on June 20, certificate 12a