Charlie Muffin (published in the United States under the title Charlie M.) is a spy thriller novel written by Brian Freemantle. The book was published in 1977.
Several more novels featuring Charlie Muffin have been published since, including Here Comes Charlie M (published in the UK as Clap Hands Here Comes Charlie), The Blind Run, See Charlie Run, The Run Around, Comrade Charlie, Charlie's Apprentice, Dead Men Living, and Kings of Many Castles.
Charlie Muffin is one of the top operatives in British Intelligence, despite his working-class background and scruffy appearance, and has been responsible for breaking up a major Soviet spy network in England, sending the network's leader Alexei Berenkov to prison for forty years. However, a new Director, Sir Henry Cuthbertson, who has a military background rather than in espionage, has reorganized the Department according to his own regimented and prejudicial ideas...which don't include a true professional like Charlie, whom he looks down upon and despises, and has appointed two of his favorites, Snare and Harrison, to major field positions, despite their obvious lack of experience.
Charlie, Snare and Harrison are on assignment in East Berlin and are about to separately make the crossing over to West Berlin. Harrison has safely made the crossing earlier and Snare is about to do so; Charlie, who will make his own crossing by car later, is very nervous about the heightened security. Snare makes an uneventful crossing, but Charlie meets up with Gunther, an East Berlin student trying to escape to the West, and gives him the car he was supposed to cross over in and necessary documents. With Charlie watching from a distance, Gunther drives the car into the East Berlin checkpoint, but the security people suddenly move in and Gunther is shot down while trying to run. Charlie makes his own crossing and meets up in West Berlin with his fellow agents, who are stunned to see him alive having seen and had reported his supposed death ... confirming in Charlie's mind that the whole business was a set-up to get him captured or killed.
In Moscow, General Valery Kalenin, chief planner of the KGB, is informed by his superiors of Berenkov's 40-year prison sentence. He is ordered to make sure that Berenkov is repatriated back to the Soviet Union within a reasonable amount of time...or else.
Charlie visits Berenkov, with whom he has apparently become friendly, in prison for an interrogation which appears to Cuthbertson, his deputy Wilberforce, Snare and Harrison to be a complete failure. Cuthbertson is determined to have Charlie demoted as far as possible and has recommended as much to his Minister. However, Charlie proves that his interrogation "was one of the most productive [he] can remember having had with a captured spy," and has provided valuable information which Cuthbertson has been unable to realize.