When my publisher suggested that I might like to write a trilogy of historical novellas set during the time of the Napoleonic Wars, I was at first reluctant. This was a period of history I knew little about but the more I considered it, the more the idea grew on me. Reading about the hugely complex, widespread and long-lasting campaigns, I very soon realised that without the intimate and specialised knowledge necessary, it would be foolhardy to try and write about battles, regiments, tactics and so forth so I directed my research to the unseen warfare of covert activities. That underbelly of every conflict.

Of course, spying on your enemy is an activity as old as history itself and has become ever more sophisticated in this digital age. The speed at which intelligence can be conveyed today would astonish the 19th century spies I read about.

And what a rich seam I uncovered about those 19th century spies, who they were and the lengths to which they went to get their information across borders.

It’s been quite a journey to learn about the extent of spying, on both sides, during the Napoleonic Wars. Not only at a diplomatic level, through overseas embassies and through the Alien Office, in London, and highly placed double agents, but among networks of ordinary people, too, who passed on maps and documents, letters, money and even arms. Smaller documents or items of intelligence could be sewn into clothing or hidden in hollowed out walking sticks or riding crops. Or even, apparently, in a hatpin (see below)! Larger items were hidden in barrels or at drop off points on the French coast such as oyster sheds. And fishermen sometimes buried items on uninhabited islets for later collection.

Both sides employed complex codes and ciphers to protect their communications. Codebooks and cipher wheels were standard kit. One captured French codebook was worth its weight in gold to the British Intelligence Service.

Until 1811, the French had lagged behind the British in the matter of devising and cracking codes but then the French invented the Great Paris Cipher. This code was so complex that the French were convinced that it could never be broken. Although documents using the code had been captured by Wellington’s forces, it’s unravelling defeated even the most skilled group of decoders and linguists based at his headquarters in Portugal.

And then, at last, a British officer, George Scovell, a gifted linguist, famously cracked it, deciphering a captured letter from Joseph Bonaparte, Napoleon’s brother. It revealed current and planned French troop movements and this intelligence led to a pivotal breakthrough in the Peninsular War.

Wellington never acknowledged Scovell’s part in this breakthrough - and Joseph Bonaparte never believed the code had been broken.

In Paris, there were underground networks of those spying for the British. Royalists, Bonapartist defectors and even double agents moved in secret, often under the noses of Joseph Fouché’s secret police (more of him later). Many were caught but a few key figures were never unmasked.

Both British and French agents used disguises, posing as merchants, priests, artists or diplomats. Some even used travelling theatre troupes as cover to move behind enemy lines. The more mundane the cover, the more convincing. Fishermen and smugglers took agents and documents to and fro across the Channel. One Jersey fisherman made nearly 200 trips across before he was caught and executed.

Women played an important role in Napoleonic espionage. Rachel Charlotte Biggs was an English writer and spy. Between 1802 and 1816, she repeatedly visited France and Napoleon controlled Europe. She corresponded with British politicians and reported her observations about military strength, industry and agriculture and the political state. Her extraordinary story is told in the novel ‘Georgian Heroine’.

Another was a countess who allegedly passed secrets to the British via coded embroidery patterns. Female spies came in many guises and used imaginative ways in which to move intelligence across borders, including hiding micro letters in hatpins!

Fishermen’s wives and daughters also put themselves in danger by passing on information and giving shelter to royalist spies.

But among the many women spies, the one who really caught my attention was Arabella Williams, originally from Liverpool. Her handler was William Wickham. Wickham was a British diplomat who used his position in Bern as a cover to gather information and coordinate royalist organisations against France. Arabella became known as ‘le petit matelot’ – the little sailor – as she had acted as a courier passing papers between France and England for a number of years disguised as a sailor, without being caught. Arabella had her own property in France where she had lived for some years, which she also used as a safe house for other agents. One of her contacts was Abbé Ratel. Early in the war, Abbé Ratel organised a network of royalists to keep watch around the port of Boulogne and provide early warning of any invasion. Reports were sent to England through fishermen recruited by Ratel – who was reputed to have a very beautiful mistress.

Arabella was described as being petite, very pretty, lively and immensely busy. The group she belonged to was extremely successful and despite the gendarmerie’s surveillance they managed to escape detection for many years. Sadly, I can find no portrait of Arabella though we do know that she was an English widow, the daughter of David Mallet, the poet and joint composer of ‘Rule Britannia’!

In France, all those spying for Britain or sympathetic to the royalist cause had to evade the clutches of Napoleon’s Minister of Police, the notorious Joseph Fouché. He was ruthless in his pursuit of British spies or those in France with royalist sympathies, torturing and executing them. He was dubbed ‘the most feared man in France’ and even Napoleon was quoted as saying ‘I fear Fouché more than all the armies of Europe’.

Fouché began his career as a maths teacher and evolved into a moderate and then radical legislator. He cultivated every political movement of the day. After preaching clemency for Louis XVI, Fouché voted to send the King to the guillotine. After writing "The first Communist Manifesto of Modern Times" he became a multi-millionaire. He led the brutal repression of an anti-revolutionary movement, earning him the nickname ‘The Butcher of Lyon’. After serving Robespierre, Fouché engineered his overthrow and rose to Minister of Police under the Directory, which he then helped to overthrow before putting his network of informants in Napoleon’s service. After turning against the Emperor, Fouché served the new King Louis XVIII – whose brother he had helped send to the guillotine. Thus, Fouché served the Revolution, the Directory, the First Empire and the Restoration. His face was said to resemble a weasel – and his less flattering portraits bear this out!

The threat from spies in France and those with royalist sympathies was very real. There were several attempts to assassinate Napoleon, the most famous being in Paris on the evening of December 24th 1800. Almost certainly funded by the British, this very nearly succeeded when a cart exploded just after Napoleon’s carriage had passed, killing bystanders.

Malmaison, Empress Josephine’s country chateau, was the site of others, including the poisoned snuff put into a replica of Napoleon’s snuff box and placed on his desk there.

Although I have changed some of their dates and locations, many of the characters mentioned in my book ‘The King’s Agent’ are based on real people including ‘Le Petit Matelot’, Pipette, the fisherman’s wife, Abbé Ratel (disguised as Father Jacques) and, of course, the infamous Joseph Fouché.

‘The King’s Agent’ is the second novella in the ‘Soldier Spy’ trilogy, following the fortunes of the disgraced soldier, Captain Will Fraser and his wounded sergeant, Duncan Armstrong, recruited by the Alien Office to spy for King George’s government.

After their first foray into the world of espionage, in ‘Traitor’s Game’ which ended in tragedy, in ‘The King’s Agent’ Fraser and Armstrong are sent to France, their mission to rescue royalist agents who have been unmasked. In constant danger, they have to embed themselves with the enemy and play a terrifying game of deception and duplicity. It is a story of love, loyalty and revenge.