James O'Neill Thrillers
Intelligence. Betrayal. Ghosts.
Out now — a two-book series

James O'Neill

The Key Series  ·  British Espionage & Cyber Thrillers

The Key Series follows ex-special forces operator James O'Neill and senior MI5 officer Sarah Sterling as they deal with the fallout from a stolen GCHQ simulation drive and the rise of The Grey Wind, a model built to detect hostile activity across the UK's power, data, and financial systems.

These grounded British espionage thrillers focus on operators, analysts, and private contractors fighting quiet wars inside networks, ports, and control rooms where a small "glitch" can carry national-level consequences.

If you read SAS and MI5 thrillers grounded in real cyber warfare and British intelligence, this series was written for you.

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"Intense, fast, hard to put down. O'Neill grabs you in the first chapter and doesn't let go." Amazon reviewer, United States  ·  ★★★★★
Available on Kindle · all major eBook platforms
Book cover of The Lost Key by James O'Neill — a British espionage thriller Book cover of The Grey Wind by James O'Neill
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Author

Personnel File  ·  Restricted
Designation James O'Neill
Service UK Special Forces
Years Active 20+ Years
Theatre Europe · Middle East · US
Current Location
Active Operations
EYES
ONLY

James O'Neill spent over twenty years in UK Special Forces and private security consulting — the kind of career that exists in operational reports and nowhere else.

He didn't set out to write fiction. He set out to solve problems: quietly, without attribution, in places that don't feature in press briefings. Over two decades, that work took him across Europe and beyond, into environments where the difference between an ally and a threat was rarely obvious, and where the ability to read patterns — not react to events — was the only reliable edge.

That discipline shapes everything he writes. His protagonist, James O'Neill, operates by a single rule: nothing is real until it happens three times, and you must witness each one. It isn't a dramatic device. It's the kind of logic that keeps people alive in environments where the obvious answer is usually planted.

His debut thriller, The Lost Key, is out now. His second novel, The Grey Wind, is also out. Both are written from the same place his career was built: close to the detail, and a long way from the noise.

Books

Book cover of The Lost Key by James O'Neill — British espionage thriller
A James O'Neill Thriller  ·  Out Now
The Lost Key
The quietest operations leave the deepest damage.

When a classified GCHQ drive disappears, there's no explosion. No headline. Just a file called Lost Key moving through the wrong hands — and a former SAS operator who knows that the quietest problems are always the most dangerous.

James O'Neill didn't go looking for this. But his name is showing up in the wrong reports.

An old MI5 contact. A hunt from Belfast to Warsaw. A drive that can quietly unlock the West's most secure infrastructure — and hostile states who are starting to realise what they're holding.

Every step is watched. Every contact is a question. Nothing is real until it happens three times.

"The twists feel earned, not forced. You keep saying just one more chapter and suddenly it's way later than you planned." Amazon reviewer, United States  ·  ★★★★

"Fast-paced without feeling rushed. The realistic feel helps it never feel confusing." Amazon reviewer, United States  ·  ★★★★★

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Book cover of The Grey Wind by James O'Neill — British cyber thriller
A James O'Neill Thriller  ·  Out Now
The Grey Wind
No sirens. No headlines. Just damage.

A year after Lost Key, James O'Neill wants a quiet life. MI5 officer Sarah Sterling wants to close the file. Neither gets what they want.

Someone is running a quiet campaign against Western infrastructure — ports, grids, financial systems — applying pressure without fingerprints, without triggering open conflict. When the attacks start mirroring a classified Red Team exercise, the question stops being who's behind it.

The question is how far their own side helped build it.

"Keeps the stakes high without relying on explosions or spectacle. Small clues unravel big conspiracies." Amazon reviewer, United States  ·  ★★★★★

"If you love Tom Clancy, give this a try. Full of action and fast-paced. Could not put it down." Amazon reviewer, United States  ·  ★★★★★

Kindle · all major eBook platforms
Amazon UK Amazon US All Retailers
Buy Direct ↗

ePub download  ·  supports the author directly

Briefing List

News & Updates

  • New Is the tradecraft in British spy fiction actually real? — Notes from the author on real tradecraft vs fiction.
  • Out Now The Lost Key is available on Amazon Kindle, all major eBook platforms, and paperback. If you've read it, a review on Amazon or Goodreads makes a real difference — thank you.
  • Out Now The Grey Wind, the second James O'Neill thriller, is also out now on Kindle and all major eBook platforms. Join the Briefing List →
  • Follow Along Behind-the-scenes updates and occasional special offers on Instagram: @jamesoneillthrillers

Contact

General & reader email info@jamesoneillthrillers.com
Film / TV / audio rights For rights, translation or media enquiries, please introduce yourself via the email above with the subject line: RIGHTS ENQUIRY — JAMES O'NEILL.
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