The appeal of Mills & Boon for readers is the promise of a happy ending. Penny always put an alpha male as the love interest and, though the books followed a theme, she brought something fresh to each one – creating believable yet escapist fiction. But it was Penny's speed and prolific output that made her so successful.
She wrote instinctively, getting a rough draft down quickly. At the beginning of her career, she wrote nearly a book a month and readers began to seek her out. She wrote on a variety of topics, from the stalwarts of romantic fiction, such as marriages of convenience, to stories involving older heroines and characters affected by the credit crunch. Halsall did not consider herself a romantic, and said: "A thoughtful cup of tea brought to your bedside each morning means more to me than the huge bouquet of flowers bought once a year."
Born Penelope Jones in Preston, Lancashire, she spent her early childhood there before moving with her family to Cheshire. Penny would recall that she began making up stories as soon as she could think; her introduction to Mills & Boon came when she was 10, via the serials in the Woman's Weekly magazines passed on to her mother, Margaret, by a neighbour.
She went to Todmorden grammar school (now Todmorden high) and then worked as a typist in Manchester. She was working in a bank when her husband, Steve Halsall, whom she had met as a teenager, bought her a typewriter to encourage her ambition to write romantic fiction.
Penny entered a competition run by the Romantic Novelists' Assocation (RNA), which brought her to the attention of an agent, and in 1979 published Duchess in Disguise, the first of 25 Regency romances under the name Caroline Courtney. She also wrote a number of books as Melinda Wright and Lydia Hitchcock.
Around the time that Duchess in Disguise was published, Penny read in a magazine that Mills & Boon were looking for new authors. "I was still an avid reader of Mills & Boon romances – on publication day I used to rush out of work to get to the local book store to grab my favourites before they all disappeared. I chose to write the kind of romance I love best – one with a sheikh hero."
Mills & Boon select most of their new authors through unsolicited manuscripts and writing competitions. The editor who discovered Penny's work in the slush pile in 1980 described her as "a raw talent – a born storyteller with a unique, intense and passionate voice". Her first book for them was Falcon's Prey (1981).
After Steve died in 2002, she found new focus in a series of novels for HarperCollins under the pseudonym Annie Groves, inspired by her mother's experiences during the second world war. Set in Liverpool and London, these focused on the home front and the changing role of women. Brimming with warmth and nostalgia, the books brought her new fans.
Penny was an active member of the RNA, supporting up-and-coming authors, and in 2011, was presented with the association's lifetime achievement award. Her last Annie Groves novel, My Sweet Valentine, along with two further volumes for Mills & Boon, The Price of Royal Duty and A Secret Disgrace (her 187th for the publisher), will be issued later this year.
She is survived by her mother, her sister Pru and her brother Anthony.
• Penny Jordan (Penny Halsall), writer, born 24 November 1946; died 31 December 2011