Henry Porter: 'Why I write about the surveillance state'

Spy fiction used to explore the murky no man's land between rival superpowers, but now the threat to freedom lurks far closer to home.

In the final pages of John Le Carré's Smiley's People, we are privy to George Smiley's thoughts as he watches Karla, the Head of the Thirteenth Directorate of Soviet Intelligence, cross a footbridge in Berlin to defect to the West. Smiley "looked across the river into the darkness again, an unholy vertigo seized him as the very evil he had fought against seemed to reach out and possess him and claim him despite the striving, calling him a traitor also: mocking him yet at the same time applauding his betrayal. On Karla has descended the curse of Smiley's compassion; on Smiley the curse of Karla's fanaticism. I have destroyed him with the weapons I abhorred, and they are his. We have crossed each other's frontier, we are the no men of no man's land."

So ends the long struggle with Smiley's nemesis and also our association with Le Carré's wily and sentimental hero - so "obscure in character and origin". Smiley has no feeling of triumph as he glimpses Karla; just a melancholy sense of his own degradation, for he is the casualty of the long game in which the players, through unremitting study of their opponent's psyche, come to resemble each other and share the same hard knowledge of the world.

At the time of publication in 1980, the Cold War seemed unending. Leonid Illyich Brezhnev was still General Secretary of the Soviet Communist Party, Moscow was worrying about a pre-emptive strike by NATO and the events of November 1989 seemed as likely as the second coming. Things were never simple then, but at least they appeared to be: west versus east; freedom versus tyranny; plenty versus the bread queue. The confrontation of the Cold War offered ample opportunity for writers of spy fiction who, following The Riddle of the Sands by Erskine Childers, the first of our breed, trained their sights on a certain evil. Le Carré was never so obvious; for one thing, there was always the agonised drama of betrayal played out in the background.

Yet even Smiley knew very well what he was fighting for and that civilisation could only be attained in a free society. So did the spies of the time. I once sat in a restaurant listening to a former intelligence officer who could not hide his emotions as he described the sacrifices made by agents on the other side of the Iron Curtain and the rather noble efforts of the British government to compensate them and their families.

But, after 1989, it was all forgotten astonishingly quickly. The emotion and tension of those years are as distant to my children as the Boer War is to me. Communism is extinct in Europe and the traces of the Wall are smothered by modern architecture, or lost in undergrowth like the trenches of the First World War. Smiley retired to one of the obscurer Oxford colleges - Lincoln, perhaps - and at length his death would have been noted in The Times, no doubt some while after he slipped across to the other side.

What is the certain evil that animates the contemporary spy writer now? Jihadism would be it, if terrorist actions and lunacy had not outstripped the imagination of any writer. Crime syndicates and arms dealers – possibly. Big business and the behemoths of the Internet age – certainly. Twenty years ago, a chief executive officer saying, as Google's chairman Eric Schmidt did, that the mission of his company was quite simply to organise all the world's information would have signalled some kind of mental disorder. That dominance will bring undreamed of opportunities for abuse in a world where more than ever knowledge is power, and I look forward to the first thriller set in a company like Google.

But it is the state, now so often propelled by the same controlling and monopolistic vices of big business, which has become the certain enemy. This is not new, but the technology at the disposal of the state is, and so is the collapse of liberal self-belief. As Russia and China developed what the Israeli academic Azar Gat described as "authoritarian capitalism", the West no longer needed to distinguish itself or define its beliefs in response to a totalitarian ideology.

We lost the use of a muscle and began to ditch the things that we stood for during the communist era. Governments, particularly in Britain, edged towards milder versions of this authoritarian capitalism, stripping the inventory of freedoms on the pretext of protecting the people, while extending the power of the state. So east and west have begun to draw inexorably towards each other, like Smiley and Karla on the bridge, which is why the conclusion of Smiley's People now seems so clever.

My last adult novel, Brandenburg, also ended on a bridge between East and West Berlin, but at the time of fall of the Wall and a moment of incredulous joy. The book describes the journey of a former Stasi agent through the October demonstrations in Leipzig and Berlin to the moment when East Germans burst into the light of a free society on 9November 1989. I was always fascinated by what had gone on in the six weeks before, and East Germans' defiance of the 80,000 members of the Stasi with their database and networks of informers.

My new novel, The Dying Light, is set in Britain of the near future and describes a society that is moving ever so gradually in the opposite direction; a country that has woken too late to a power grab by the state.

The main character is also a former spy. She has returned to Britain after eight years in New York as a successful corporate lawyer. Sceptical and rational, Kate Lockhart is not the sort of person to succumb to a conspiracy theory but, like her collaborator and fellow MI6 officer Peter Kilmartin, she begins to see forces in her own society nearer to those that existed in the old Eastern Bloc.

These two spies are disposed to trust the British state despite its obvious faults and believe, as I do, that it can be a force for good. So it takes them some time to understand that the government has colluded with an international systems company to institute the beginnings of a discreet 21st-century version of totalitarianism. I don't envisage some Orwellian dystopia but rather a country where everything appears pretty much as it does today. People shop in farmers' markets, listen to The Archers, go to the match and plod along in the humdrum way of the English.

It is just that they are watched a great deal more, and that scrutiny by the state of the individual is responsible for a profound change in their lives, though somehow only a few have realised. The struggle against the criminal state no longer takes place across No Man's Land but begins in the rather less bleakly romantic setting of a square in an English market town, which happens to bear a striking similarity to Ludlow. The Dying Light is a political thriller, so why deploy characters better suited to the long vigil at a border crossing, or an undercover job in some distant embassy? The answer is that spies are familiar with the despotic instinct, have the necessary skills to outwit a government that has granted itself so many authoritarian powers and – crucially- are quick to understand that all communications and any information held digitally are compromised.

Spies are used to conveying information in the physical form - a letter or document that cannot be intercepted - and they know how to evade surveillance, even in a country like Britain where the authorities has given themselves powers to watch every street corner, monitor every car journey in real time and are about to seize access to all emails, Internet connections, text messages and phone calls. In these circumstances, the old tradecraft of the Cold War is very useful.

So my two intelligence officers, trained to look outwards, are confronted by a domestic foe that possesses no distinct markings. Questions of loyalty arise and they must contend with the lack of any real evidence, because this enemy leaves almost no trace of its activity apart, perhaps, from the haunting of a group of ordinary people in the town where the story begins with the inquest and funeral of the head of the Joint Intelligence Committee.

The enemy within is nothing new, nor is the idea that a democratic state would round on its own citizens. What interested me as a thriller writer was the difficulty my hero would face in a country that is anaesthetised to the reality of its politics. This seemed to present as testing a practical environment as anything in the old GDR which, incidentally, collapsed at the moment the World Wide Web was invented by Sir Tim Berners Lee and just before wireless technology had exploded. Until that moment, databases mostly existed in the physical world of paper and filing cabinets.

I have often wondered whether the opposition that formed in East Germany 20 years ago would have been confounded by modern technology or would have used it to organise itself more effectively, as happened in the revolutions in Serbia, Georgia and now Iran. When it comes down to it, I suspect that the cattle prod trumps Twitter. Opposition still takes guts and cunning whatever the circumstances, and that is what my spy Kate Lockhart has in spades. My book is a thriller but in the words of Erskine Childers, this is "a story with a purpose".

Henry Porter's 'The Dying Light' is published this week by Orion