James O’Neill Thrillers | The Lost Key
New release · Now on Kindle

The Lost Key

A missing USB drive. A training exercise that was never meant to touch the real world. A country sleepwalking into its worst case scenario.

A missing USB. A ‘test’ that was never meant to reach the real world. When a GCHQ training drive packed with simulated access routes vanishes, ex-Special Forces operator James O’Neill is pulled into a covert hunt across Europe before hostile states realise the Lost Key unlocks a nation’s defences.

Available as Kindle eBook and other eBook platforms · A standalone James O’Neill thriller
Book cover of The Lost Key by James O’Neill
Also available to read on your Kindle, tablet, or phone.

Author

James O’Neill is a former UK Special Forces operator with nearly two decades of service, now turned covert security consultant, the person governments call when a problem does not exist on paper. He lives by a simple creed: nothing counts until it happens three times, and you have to see all three. He watches patterns, not headlines, behaviour, not promises. That mindset drives every decision he makes in The Lost Key.

James, now retired, writes from the same world his character inhabits: deniable operations, blurred lines between allies and enemies, and the quiet, necessary work done far from cameras and podiums. The result is a protagonist who feels lived-in rather than invented, a man shaped by nearly two decades in the shadows, old loyalties, unfinished business, and the knowledge that security is always more fragile than it looks.

Behind the fiction: The tradecraft, tension and compromises in these stories are drawn from real patterns of life, only the names have changed.

Books

A James O’Neill thriller
The Lost Key - OUT NOW
A stolen key. A silent war. One man caught in the crosshairs of both.

When a piece of classified code vanishes from GCHQ, London doesn’t hear an explosion. It feels a silence.

The file is nicknamed the Lost Key, a powerful cryptographic tool capable of quietly unlocking secure systems across the West. Whoever controls it rewrites financial records, crashes infrastructure, and turns trusted networks into weapons.

Former SAS operator James O’Neill thought he’d left that world behind. Now working as a security consultant, he’s dragged back into the shadows when an old contact in MI5 slips him a warning: the Lost Key is on the move, bodies are starting to fall, and his name is suddenly appearing in the wrong briefings.

MI5 handler Sarah calls in the one man she trusts to retrieve it without leaving a trace: James O’Neill, ex-Special Forces, now a freelance security operator who lives by a simple rule, nothing counts until it happens three times, and you have to see all three.

From Belfast and London safe houses to Warsaw server rooms and shadow markets where data is traded like weapons, James is pulled into a hunt where every move is watched and every ally might be compromised. It becomes clear the Lost Key isn’t a test object gone astray.

Format: Kindle eBook, and all other eBook platforms
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Upcoming
The Grey Wind
A new James O’Neill thriller, set twelve months after The Lost Key.

The Grey Wind stays under wraps for now. Work is in early stages and details will land first with readers on the Briefing List. Expect the same grounded tradecraft, pressure, and hard choices that define James O’Neill’s world, with new ghosts from the past beginning to surface.

Briefing List

News & Updates

  • [Launch] The Lost Key is now live on Amazon Kindle including other platforms.
  • [Writing] The next James O’Neill thriller, The Grey Wind, is in early development. Briefing List readers will see progress and pages first.
  • [Behind the scenes] Follow @jamesoneillthrillers on Instagram for redacted pages, working notes and launch news. Updates are also available on X via @JONeillBooks

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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