Every book starts with a moment of inspiration; a germ of an idea that develops and grows and, just occasionally, ignites an all-consuming passion.

Back in 2014 I was in need of just such an idea after my then publisher decided my embryonic career as a thriller writer had come to a natural end. I needed to write two books a year to maintain the unchanged lifestyle I’d optimistically promised my wife when I gave up the day job. Where did I go from here?

As a fledgling writer I’d dabbled in crime and quite enjoyed it. Clearly, there was a huge market for crime fiction, but to make a mark in the genre I had to come up with something special. One of my uncles, sadly passed away by then, was a Pole, Kazimierz Gardziel, known to one and all as Yank, a former soldier and something of a legend. After some thought I decided to set my book in Poland, specifically in Warsaw, and dedicate it to a man whose infectious spirit of adventure had brightened up my early life. There’d be four novels – the Warsaw Quartet – and the first would be called Blood Roses.

Author Douglas Jackson PIC: Ian Rutherford

I had no idea then of the challenges I’d face in recreating a city that had been almost literally wiped off the map on the orders of Hitler, or researching the lives of its citizens when the primary sources were almost all in Polish, a language of which I couldn’t speak a word. Nor did I realise that in telling the story of Warsaw’s ordeal during five years of brutal Nazi rule, I’d also uncover the truth about Uncle Yank’s astonishing heroism.

My novels are based on a simple premise. I put the main character in a place and a time of extreme peril and challenge them to get out of it. In one of my early books I’d explored the theme of collaboration, and the compromises a conquered people have to make to survive. From what I knew of Warsaw’s history, it was plain that its citizens would have faced such life or death decisions on a daily basis. I decided my detective, Jan Kalisz, son of a Polish miner and a German housewife, would be forced to lead a dangerous double life, operating as a resistance agent while apparently collaborating with the Nazis. Not even his family would be allowed to know the truth.

When the niece of a Nazi general is found murdered in macabre circumstances, Kalisz’s father-in-law is among the hostages chosen to be shot unless her murderer comes forward. Kalisz’s colleagues are certain the killer is a Pole, but gradually Kalisz realises the murder is linked to other killings of less interest to his new masters, and that the man he’s looking for may be one of the conquerors. Soon he is hunting a serial killer dubbed The Artist.

Warsaw now is not the Warsaw of September 1939. In October 1944 every building of any consequence was blown up or burned after the bloody, abortive uprising by the Home Army. How, then, to ensure that the streets my fictional Jan Kalisz walks were the ones that existed at the time the book is set?

Luckily, I stumbled upon an obscure interactive website that contained a map of most of Warsaw’s 1939 streets, complete with photographs and detailed histories of the individual buildings. The site was entirely in Polish, so I had to develop a system of cutting and pasting information to Google Translate, then copying the translation into a file for each street. I then discovered I could input the addresses into another site – again in Polish – that gave me the actual names of the families who lived there in 1939, and all too often their unfortunate fate. In one, a Polish surgeon had crossed into the ghetto to carry out an operation on a Jewish woman. Midway through the operation, the SS burst in, shot the patient where she lay, and hustled the doctor into the courtyard where he was massacred with the block’s other residents.

I’d always known Blood Roses and its sequels would be dark books, but scenes like this, and much worse, quickly confirmed that researching and writing them would become a test of my mental fortitude as well as my literary skills.

Yet all was not darkness. At one point in my research I posted a question about pre-war Polish life on a Facebook page recording the history of the First Polish Armoured Division. At about this time Yank’s daughter in Australia sent me some old pictures she had of her dad. One of them was of a very young Yank in uniform and looking very annoyed at being photographed, and he was wearing a medal. Here was the first confirmation that the family legend might have some substance.

When I put the picture on the website someone very quickly identified the medal as the Silver Cross of the Virtuti Militari, the Polish equivalent of the Victoria Cross. This discovery started a wave of information from the enthusiasts on the site. Kazimierz was identified as a reconnaissance motorcyclist in the Tenth Dragoons, a tank regiment which had landed in France a month after D-Day and fought its way across Europe.

He’d been wounded on October 6 1944 near the Dutch-Belgian border when a platoon of the battalion’s Sherman tanks were ambushed by Panzers. Without any thought for his own safety Yank had driven into the heart of the fighting on his motorcycle to help the trapped and injured tankers. Despite being badly wounded in the hip he’d then led 18 of his comrades to the safety of the Allied lines. My Polish uncle was a true hero.

Prior to D-Day, Yank had been stationed in the Borders. He met my aunt Margaret at a dance in Jedburgh and they’d married not long after. By the time he fully recovered, the war was over. He and Margaret set up home in Rugby and he worked on a car production line in Coventry. Over the years he was a frequent visitor to his old stamping grounds and he'd lead ten-year-old me on route marches across the moors to remote hill lochs to fish. On warm summers’ days we’d don trunks and he’d teach me to guddle trout up the Bowmont Valley. If fish wasn’t on the menu, he’d appear with a hare or a pheasant that had miraculously leapt into his arms. He never talked about the war.

If Yank had lived to see the dedication to him in Blood Roses, he’d have puffed out his cheeks, rolled his eyes and called it nonsense. But, secretly, I’m pretty certain he’d have been proud.Sadly, publishers weren’t as confident of Blood Roses’ potential as I was, and it didn’t sell. Then in 2023 my agent thought it was worth pitching my unpublished novels to a new, innovative publisher called Canelo. The upshot was a contract to deliver four books – Blood Roses, Blood Sacrifice, Blood Vengeance, and Blood Enemy – chronicling Jan Kalisz’s struggle to survive during five years of occupation in a Warsaw where death lurks round every corner.

Blood Roses is published in hardback by Canelo today, priced £16.99. Douglas Jackson is the author of 18 novels across three genres and has been published in 12 languages. He lives in Stirling

The book inspired by my heroic Polish uncle