Billy Fisher lives in Yorkshire with his parents and grandmother, and works as an undertakers' clerk overseen by the rigid Mr. Shadrack. Billy wishes to get away from his stifling job and family life. To escape the boredom of his humdrum existence, he constantly daydreams and fantasises, often picturing himself as the ruler and military hero of an imaginary country called Ambrosia. He also makes up stories about himself and his family, causing him to be nicknamed "Billy Liar". Billy has further complicated his life by proposing to two very different girls, the sheltered, virginal Barbara and the tough, brassy Rita. He has given the same engagement ring to each girl and lies constantly to get it back from one and give it to the other, eventually resulting in a family row when Rita discovers he has lied about the ring being at the jewellers. Billy also finds himself attracted to his former girlfriend Liz, who has just returned to town after extensive travels. Liz is a free spirit who, unlike anyone else in town, understands and accepts Billy's imagination. However, she has more courage and confidence than Billy, as shown by her willingness to leave her home town and enjoy new and different experiences. At work, Billy is tasked with mailing out a large shipment of advertising calendars to potential customers, but instead hides the calendars and keeps the postage money. He is eventually found out by Shadrack, who refuses to let him resign from his position until he pays back the postage money. Billy aspires to get a more interesting job as a scriptwriter for comic Danny Boon, but when Boon comes to town, he is not interested in Billy's overtures. Under pressure, Billy ends up making dates with both Barbara and Rita to meet each one on the same night at the same local ballroom. There, the two girls discover the double engagement and begin fighting with each other. Meanwhile, Billy encounters Liz and shares a romantic interlude with her outside, during which he proposes to her and she accepts. She urges him to accompany her to London that evening, and he goes home to pack his bags, only to find his grandmother has fallen ill and been taken to hospital. Billy joins his mother at the hospital just in time to learn his grandmother has died. He then continues to the station to meet Liz, and the couple board the train, but at the last minute Billy disembarks with the excuse of buying some milk to drink on the journey. By the time he gets back to the train, it is pulling out, with an understanding Liz at the window and his suitcase left behind on the platform. Alone, Billy walks the dark deserted road back to his home, imagining himself leading the marching army of Ambrosia.
The film marked the breakthrough role of Julie Christie, who was nominated for a BAFTA award for her performance as Liz. The film was also nominated for another five BAFTAs. In 1999, the British Film Institute named Billy Liarnumber 76 in its list of the top 100 British films. In 2004, Total Film named Billy Liar the 12th in its list of the greatest British Films of all time.
