A Maida Vale author has beaten more than 1,800 others to be named runner-up in a prestigious inaugural short story competition with a tale about mushrooms, love and death.

Chioma Okereke, who lives in the Harrow Road, came second for her story Trompette de la Mort in the first Costa Short Story Award, announced alongside the Costa Book Awards on Tuesday night.

The recognition is further endorsement of her talent after her debut novel Bitter Leaf was shortlisted for the Commonwealth Writers’ Prize – Africa Best First Book, in 2011.

The 36-year-old said: “It was really exciting and I’m really happy. Being there, in the line-up with the other finalists, made it more real.

“It’s still a bit of a blur to be honest. It is incredible, because so many people send things in. It is pretty phenomenal because you don’t know what these judges are thinking.”

The prize is decided by public vote from a shortlist selected by a judging panel. The authors are kept anonymous at the shortlisting stage, and Chioma discovered on the night that the judges thought Trompette de la Mort was written by Choclat author Joanne Harris.

“That was the biggest compliment,” she said. “It is one of those things where there is an element of craftsmanship on one level, and luck on another.”

Set in a French town, Trompette de la Mort is a woman’s evocative confession to her first-born child, the strikingly honest story of a mother and a killer that takes in love, sex, food, lies, life and death – all in less than 4,000 words.

Talking about the inspiration behind the tale, Chioma said: “Every couple of months last year I would get the papers on the way home and I would see a story about a woman who had killed her children.

“At the same time I met a friend of mine’s father-in-law who had just published a book about mushrooms, and that set itself in my mind.”

She said the idea of poisonous mushrooms “fused itself with my ideas” after hearing about one type, the trompette de la mort, on a TV cooking show.

“To be honest I am very lucky because I am not a natural short story writer,” she said. “I am not quite sure what a short story is, but as soon as [the woman] identified herself as a strong character it started to take shape. And I’m not a hater of mushrooms, but they’re not my favourite thing either!”

She added: “I didn’t spend a long time on it to be honest. I think I have spent a lot longer on less successful stories. It was trying to understand how people can do such things. I have tried to write a very natural story about something that is quite unnatural.”

Chioma is already working on her next book.