Written in response to the positive public reaction to his previous novel, The Spy Who Came in from the Cold, the book explores the unglamorous nature of espionage and the danger of nostalgia.

Surviving on long past memories of its aerial reconnaissance missions during the Second World War the organisation has been reduced to a skeleton crew consisting of Leclerc, a nostalgic former air commander who now languishes in bureaucracy as Director; John Avery, his 32-year-old aide who took the job after failing as a publisher; Wilf Taylor, a middle-aged man who views the job as his last chance at glory; and Adrian Haldane, a pompous intellectual in ailing health whose research on the Soviet Union and East Germany has been the sole reason for departmental funding from Whitehall.

Languishing in the mundanity of bureaucratic battles and inconsequential desk work, the Department desperately desires the opportunity to regain its standing in the intelligence community, as well as to gain a one up against their now superior rivals in the Circus, headed by chief "Control" and his second-in-command, George Smiley.

With the Cuban Missile Crisis in mind, they quickly manufacture a plan to act, and bribe a commercial pilot to stray off course to photograph the site in the hopes of verification.

Hoping to stave off any apprehension from Leiser, Haldane and Avery lie to him and tell him the Department is still the dominant espionage unit and is operating at the size it was at its wartime peak.

Towards the end of his training period, however, Leiser begins to improve, and is able to pass all of his field readiness evaluations, including sending Morse code messages whilst changing frequencies every two minutes to avoid detection, which he had previously struggled with.

The defector has a history of trying to sell fabricated "information" to Western services, the photographs he provided as evidence are dubious, and Leiser was unable to corroborate any part of his story.

While le Carré had intended that novel as a deconstruction of the mythos that had sprung up around MI6 in the post-war era, he was disturbed that most readers in the United Kingdom regarded it as a romanticisation of spy life and saw its protagonist, Alec Leamas, as a tragic hero.

Still wanting to convey the same message, le Carré wrote The Looking Glass War as an explicit satire about a spy operation that was completely futile and pointless and the failure of which could not be considered a tragedy.

He further sought to examine British nostalgia for the "glory days" of World War II, and how an ongoing fascination with Britain's victory in the conflict informed contemporary attitudes towards espionage.

Broadcast on BBC Radio 4, it starred Ian McDiarmid as Leclerc, Piotr Baumann as Leiser, Patrick Kennedy as Avery, and Simon Russell Beale as George Smiley.