The former war reporter Jack Fairweather has won the Costa book of the year award for The Volunteer, his biography of a Polish resistance fighter who voluntarily entered Auschwitz in order to reveal its horrors to the world.

Fairweather’s life of Witold Pilecki, a member of the Warsaw resistance who infiltrated the concentration camp and encouraged rebellion, was hailed as “a book that needs to be read” by the chair of judges, Sian Williams.

The Volunteer by Jack Fairweather review – the hero who infiltrated Auschwitz Read more

Fairweather dedicated the win to Pilecki’s two children, Andrzej and Zofia, who heard of their father’s execution as an “enemy of the state” under the communist regime when they were children. “In 1948, they sat in their school in communist Poland and listened as it was announced over the tannoy system that he had just been executed as a traitor and enemy of the state,” he said. “For the next 50 years they had no idea what their father had done in Auschwitz.

“It’s been my absolute pleasure and privilege of my writing career to be able to share his story with you.”

Williams praised Fairweather’s reporting – he used, referenced and translated thousands of primary sources while researching Pilecki’s life – and said the story of resistance in the camp was still an untold part of its history.

“It reads like a thriller, it doesn’t really read like a biography at all and yet you don’t feel as though it’s overdramatised in any way,” she said. “This is a story that none of us had heard before and it deserved to be shouted about. It’s an extraordinary book.”

Fairweather describes how Pilecki, a former cavalry officer in the Polish army, volunteered to be captured and taken to Auschwitz, where he began organising an underground network.

Starting on 19 September 1940 with the Nazi purge of the Jewish and Polish professional class, Fairweather weaves Pilecki’s story alongside a story from outside the camp where his calls for the allies to bomb the camp were ignored. Reportage and quotes gathered from primary sources are combined to create a biography that is driven by the narrative of a resistance fighter’s attempt to bring down the most notorious death camp of the second world war.

Pilecki said that because of the horrific conditions in the camp, “some slithered into a moral swamp. Others chiselled themselves a character of finest crystal.” The resistance fighter smuggled out messages about the “monstrous torture” being endured by prisoners but the outside world did nothing.

The overall award aims to reward the year’s “most enjoyable” book, and is selected from the winners of five sub-sections: first novel, novel, biography, poetry, children’s book. Fairweather’s biography beat first novel prize-winner The Confessions of Frannie Langton by Sara Collins, novel winner Middle England by Jonathan Coe, Mary Jean Chan’s poetry collection Flèche, and Jasbinder Bilan’s children’s book Asha and the Spirit Bird.

Past winners include Hilary Mantel, Helen Dunmore and Sebastian Barry. Bart van Es won last year’s award with another forgotten story from the second world war, his biography The Cut Out Girl. The £30,000 award also guarantees a strong performance in sales.

Williams said anniversary events this week to commemorate the 75th anniversary of the camp’s liberation did not influence the decision. “We all felt that it was a book that stood out on its merits, whenever it was published. We didn’t feel a particular way towards it because it’s a prescient book for the moment.”

However, she said, the book was very timely. “At the moment hate speech is on the rise, hate crime is on the rise, antisemitism is on the rise and you just hope today that there are those voices which need to be heard and will keep going until they are.”

This year’s judging panel included the comedian and author Ben Miller, the actor Hugh Quarshie and the presenter Anneka Rice.