Irish playwright Abbie Spallen has won one of the world’s richest literary awards, the Windham-Campbell Prize, worth $150,000 (€138,000).

She experienced her own moment of high drama last week when prize director Michael Kelleher broke the news out of the blue by phone.

Judged anonymously, the prize has no submission process, public longlist or shortlist, and so writers are unaware that they are in the running.

“I thought it was a scam at first,” said Spallen, who is from Newry, Co Down. Thanking the donors, she said: “I am beside myself to receive this award. Both in monetary terms and as a recognition of my work.

“I do try to be brave, and I’m aware that I can produce work that may not be palatable to all. Sometimes that can feel quite the lonely pursuit. Thank you so very much. I’ll stagger on. Less lonely than before.”

The award citation reads: “Abbie Spallen’s plays confront audiences with all the awkward questions, reminding us with thrilling proof that theatre can still be urgently necessary.”

Spallen is working on plays for the Abbey in Dublin, the Lyric in Belfast, and the National Theatre, Royal Court and Tricyle Theatre in London but plans to put some of her prize money towards writing and directing her first short film.

Fintan O'Toole, literary editor of The Irish Times, wrote of her latest play, Lally the Scut, last December: "This brave, brilliant, darkly hilarious Swiftian satire on the peace process is my Irish play of the year."

Last night, he said: “Abbie Spallen’s imaginative daring matches her political courage. There’s a fieriness to her work that I really admire – it’s angry and tough and anarchic.

“But she’s also deeply serious and has a sense that drama ought to matter in the political world. It would be great if an award like this gives her the time and the freedom she needs and deserves.”

Spallen’s work is haunted by the history and geography of her native land, a borderland of bogs, caves, hills, and marshes, a place where the past is never really dead.

She has described her work as “uncomfortable theatre” but while her plays are undeniably dark, there are flashes of beauty, humour and tenderness in their depiction of life on the margins.

The playwright is no stranger to awards. She received a £15,000 grant from the Arts Council of Northern Ireland in 2014 to work on a stage musical. In 2009, she received the Stewart Parker Trust New Playwright Bursary.

Her play, Pumpgirl, was co-winner of the 2007 Susan Smith Blackburn Prize, was nominated for an Irish Times Theatre Award for best new play and adapted for television by the BBC.

She also won the Tony Doyle Award for screenwriting for her BBC screenplay, Seven Drunken Knights. Her other plays include Strandline (2009) and Bogwog (2005).

The Windham-Campbell Prizes, administered by the Beinecke Rare Book & Manuscript Library at Yale University, were established in 2013 with a gift from the late Donald Windham in memory of his partner of 40 years, Sandy M Campbell.

They recognise exceptional writers of fiction, nonfiction and drama who write in English. This year's other recipients are Tessa Hadley, Helen Garner, Branden Jacobs-Jenkins, Hannah Moscovitch, CE Morgan, Jerry Pinto, Hilton Als and Stanley Crouch.

Past recipients have included the late James Salter, Naomi Wallace, and Teju Cole.

The prizes are among the world’s richest. The Man Booker Prize is worth £50,000 and the International Dublin Literary Award €100,000.