Once upon a time, Andy Mulligan, an English teacher in the Philippines, wrote a funny book.
So amusing was Ribblestrop that it was named one of the six funniest children's books published in 2009 (the very funniest was Philip Ardagh's Stinking Rich and Just Plain Stinky).
Mr Mulligan's pupils at the British School in Manila were so delighted with their teacher's account of an anarchic English school that they decided to help him. They hit local bookshops and hid Jeff Kinney's best-selling Diary of a Wimpy Kid behind countless copies of Mr Mulligan's book.
And Mr Mulligan, inspired by his agent, readers and most of all his pupils, carried on writing. He produced a thriller, Trash, about three "dumpsite" boys who pick through rubbish and uncover a mystery, which was published in 2010, and Ribblestrop Returns, released earlier this year.
He then took advantage of this success to take some time out of the classroom to focus even more on writing. But that did not go well.
"I took a sabbatical of six months and found it really difficult," he says. "It was really dispiriting. For example, you'd meet up with friends and they'd have things to talk about. But what could I say? 'Well, I had another go at chapter five'
"So when people say, 'You can give up teaching now' - which is the dream of many teachers - it's just not on the cards for me. I'd go berserk if I wasn't teaching. But I am lucky to work in international schools with friendly children and good colleagues. I'm very privileged."
So back he went to the chalk face. Mr Mulligan, 47, now works full-time at the ABC International School in Ho Chi Minh City, Vietnam, and writes in his spare time.
But his decision has created an unusual double life. By day, he prepares his pupils for their English exams; by night he checks out exciting emails about film deals.
"The first thing I heard about a film interest in Trash was when my agent, Jane Turnbull, had lunch with the film agent Jenne Casarotto," says Mr Mulligan. "Jane was telling her about Trash and Jenne said it sounded very good.
"I was working in Manila at the time and I woke up one morning to this email updating me. Jenne said she had this producer, Kris Thykier, who wanted to buy the rights.
"A couple of days later, Kris emailed to say Stephen Daldry (director of Billy Elliot) wanted to do it.
"Then, 24 hours later, Stephen was on the phone. I could hardly hold the receiver I was so nervous. I had to have a stiff whisky before I even spoke to him. Then I asked, how had he come to read it?"
It turned out Mr Daldry had come across the book almost by luck. He was leaving his home en route to the airport when he realised he had not packed any reading matter. That morning he'd been sent Trash, so he grabbed it and read it on the plane.
By the time he stepped off, he wanted it to be his next film.
Mr Mulligan, who worked as a theatre director before becoming a teacher, later had a meeting in London with Mr Daldry and arguably the most successful man in British cinema, Richard Curtis, who had agreed to be the scriptwriter.
"It became very clear," says Mr Mulligan, "although Richard was too polite to say so, that I'm not a screenwriter and have no idea how movies are made.
"They had lots of ideas and wanted me to check if they had a full understanding of the characters and plot - they wanted to assure me that they 'got' the book. But I think it's ever so important that Stephen and Richard get on and do it how they want to do it."
Mr Mulligan signed a 50-page contract and is now crossing his fingers, waiting to hear what happens next. Or he would be, if he wasn't working on the third Ribblestrop book - and, of course, teaching.
"It's quite phenomenal," he says. "It doesn't seem real to me, let alone anyone else. When I started here in Vietnam, the children were looking me up on websites and the rumours went around. But it's a weird thing: it doesn't affect my teaching because, for the children, there is so much going on in their own lives.
"That bit of gossip about their English teacher signing a movie deal was hot for about 10 minutes. Sometimes they may use it to distract me and they ask for updates.
"But it's not like I'm visiting the film set. It's not like Stephen Daldry is ringing me up every day asking for advice."
'IT WAS A CHANCE TO WRITE A THRILLER'
Oscar-nominated screenwriter Richard Curtis is adapting Trash for the screen. Here, he explains why he is excited about the project:
"I'm a very bad book reader. I only get through about four books a year, and yet this was one I read in a day. It's about three boys, and as the father of three sons that's a good start. But I suppose what really attracted me was the chance to write a thriller - an adventure, something with a really dynamic plot, and twists and turns and fear and violence and high stakes - after writing quite a lot of films about kissing.
"In the book, there is also something interesting about poverty and corruption and the value of people who society doesn't put any value on at all.
"And it's quite a funny book, with jokes I hope I can try to turn into dialogue - and it's full of great characters, who I can just steal."