The Cobras of Calcutta: The Decipherer's Chronicles

In the fifty years between 1757 and 1815, Britain lost an empire, won another and emerged from the epic Napoleonic wars as the greatest power the world had ever seen.
But no empire comes about by accident. The spread of British power was fuelled by the ambition and zeal of a host of larger-than-life personalities. But while history records the actions of those who chose familiar public paths to make their mark, others who served under a necessary cloak of silence have left no memorials. There were men who gave their whole lives to these hidden struggles.
At the centre of these machinations lay one secret institution: the Decipherers - the code breakers, the interceptors of letters and messages, the analysers of intelligence - constantly locked in silent deadly combat with the Cabinet Noir, the Black Chamber, the secret agency of Britain's greatest enemy, France. Working tirelessly with the Decipherers was a small number of trusted agents whose secet trade carried by neccessity into the deepest conflicts of empire and Alistair Douglas was one of them...