
The Lost Key
James O'Neill(Author)
James O'Neill (Publisher)
Published on 3. December 2025
Book
Paperback/Softback
318 pages
979-8-232-54803-2 (ISBN)
Description
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 can rewrite financial records, crash infrastructure, and turn 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.
From back alleys in Belfast to anonymous server farms outside Warsaw, James is forced to track a threat that moves at the speed of data and kills without leaving fingerprints. A ruthless Belfast crime boss, a compromised insider inside the British state, and a faceless group of foreign operators all want the same thing and they all think James is in their way.
As the digital trail twists into a very human conspiracy, James has to decide who he can trust, what he's willing to sacrifice, and how far he'll go to stop a weapon that doesn't fire bullets... it erases truth.
If he fails, the first thing to disappear will be the evidence that he ever tried.
The Lost Key is a high-velocity British espionage thriller that blends boots-on-the-ground tradecraft with modern cyber warfare and political intrigue.
Perfect for readers who
Relentless pacing and grounded action
Ex-military protagonists with a moral code and a past that won't stay buried
Intelligence agencies, covert operations, and shadow wars in Europe
Tech-driven cyber weapons, compromised networks, and weaponised data
The feel of Lee Child, Tom Clancy, and Mark Greaney in a modern British setting
Start The Lost Key today and step into a world where the most dangerous weapon on earth fits on a single drive and everyone is already at war for it.
More details
Series
Language
English
Product notice
Paperback (trade)
Unsewn / adhesive bound
Dimensions
Height: 216 mm
Width: 140 mm
Thickness: 19 mm
Weight
450 gr
ISBN-13
979-8-232-54803-2 (9798232548032)
Copyright in bibliographic data and cover images is held by Nielsen Book Services Limited or by the publishers or by their respective licensors: all rights reserved.
Schweitzer Classification
Person
Before fiction, James O'Neill spent close to two decades in UK Special Forces and high-risk security work - operating across Europe, the United States and the Middle East in environments where the official version rarely matched what actually happened on the ground.
Those years fixed his interest on how surveillance works in practice, how operations fail in silence, and how decisions made in closed rooms alter lives far from any camera.
His debut novel, The Lost Key, opens a series of British espionage thrillers built on real tradecraft, modern geopolitics, and the blurred edge where cyber and human intelligence meet. Book two, The Grey Wind, continues the story of ex-SAS operator James O'Neill and MI5 officer Sarah Sterling as quiet pressure builds across the UK and Europe.
Away from the keyboard he continues to work internationally in security, risk and critical infrastructure. He divides his time between the United Kingdom and airport departure lounges - usually with a notebook in hand and the next operation already forming in his head.