This time last year Lisa Ballantyne was writing a novel in secret, working at Glasgow University by day and writing at least 1000 words a night.

Now a year later, the Scottish writer has an agent, a major publishing deal, a praised debut novel and has been picked as one of the books promoted by TV presenters Richard Madeley and Judy Finnegan for their popular annual book club.

Ms Ballantyne has now resigned from her post at the university and has embraced the life of a full-time novelist following the success of her debut, The Guilty One.

Ms Ballantyne wrote the novel while working for the university, and after she was signed with a literary agency, it had become the buzz of the annual Frankfurt Book Festival.

It was sold by her publisher, Little, Brown, to publishers from 20 countries including France, the US, Brazil and China.

Last week, Madeley said of the book: "One of the most readable, emotionally intense novels of the year, and a debut one at that.

"Lisa Ballantyne pulls off the key writer's trick of getting us to care about the characters; by the end of the first chapter, you will be comprehensively on the hook."

Ms Ballantyne, 38, originally from Armadale in West Lothian and who studied English at St Andrews, spent most of her 20s working and living in China before returning to Scotland in 2002.

The Guilty One has now been sold to more than 20 countries, including a six-figure deal in the US, affording the writer enough time to leave her work at the university. She is now working on her second novel.

"So far being a full-time writer is going really well, I have been working really hard finishing the second novel," she said.

"It was a strange moment leaving work [in February] but it is wonderful, being able to write every day and having so much time to do what I want to do.

"It was exciting being picked up by Richard and Judy, I was interviewed by them. They were very nice to me and said they enjoyed the book. Everyone has been so supportive."

She added: "When we got the US deal, I was standing on a dark railway platform by myself, heading home. I couldn't believe it was happening."

A spokeswoman for Little, Brown said: "It was always clear that we had something rather special on our hands with The Guilty One – my colleagues and I were completely bowled over by it from the very beginning.

"We were delighted when it was chosen for the Richard & Judy Book Club as we've seen how inclusion in the selection, particularly for a debut author, can provide a fantastic launch-pad for a long-term writing career.

"We're so proud to be publishing Lisa and with such an exceptional first novel we couldn't be more excited about what the future holds for her."

The Richard & Judy Book Club was added as a regular segment of the married presenters' TV show in 2004 and its impact was compared to Oprah's Book Club in the US.

The Richard and Judy Book Club returned in autumn 2010 and is run online in conjunction with retailer WH Smith.

The TV presenters have become authors themselves: Madeley is currently writing his second book, while his wife is writing her first novel.

Little, Brown say The Guilty One is a "hugely compelling and moving tale of how tied we all are to our pasts" and have compared it to the writing of S J Watson, Nicci French and Sophie Hannah.

The novel's main character, Daniel Hunter, is a solicitor in London who has to deal with the case of an eight-year-old boy who has just been accused of murdering a six-year-old. The case reminds Daniel of his own troubled childhood, and of Minnie, the woman who adopted him.

Of her next book, Ms Ballantyne said: "It is still fairly psychological but it is different – there is no crime."