The minuscule European Duchy of Grand Fenwick is bankrupted when an American company comes up with a cheaper imitation of Fenwick's sole export, its fabled Pinot Grand Fenwick wine. Crafty Prime Minister Count Mountjoy devises a plan: Grand Fenwick will declare war on the United States, then surrender, taking advantage of American largesse toward its defeated enemies to rebuild the defeated nation's economy. Duchess Gloriana is hesitant but agrees to the plan. Mild-mannered game warden Tully Bascomb is charged as Field Marshal to lead the Grand Fenwick troops, aided by Sergeant Will Buckley. The contingent of 20 soldiers in medieval chain mail books passage across the Atlantic on a small merchant ship, arriving in New York Harbor during an air-raid drill that leaves the city deserted and undefended. They chance upon a civil defence truck and are mistaken for invading Martians, prompting an investigation by blustering but ineffectual General Snippet. Puncturing the tyres of the general's jeep with their bows and arrows, the Grand Fenwick troops take him and four NYPD officers hostage. Still looking for a place to surrender, Tully and Will stumble across Dr. Alfred Kokintz, whose invention of the Q Bomb – capable of destroying an entire continent – has prompted the defense drills. He has built a football-sized prototype of the unstable bomb, which Tully takes possession of. With Kokintz and his attractive daughter Helen as additional hostages, Tully declares victory and returns with them to Grand Fenwick. The duchess indulges Tully's victory, and the prime minister resigns in disgust at Tully's blunder, leaving him as acting prime minister. When the incident is discovered, the U.S. government is thwarted from retaking the weapon and hostages by force, fearing the dishonor of attacking such a small and defenseless nation. Instead, they send the U.S. Secretary of Defense to discuss terms of surrender and get back the bomb. Meanwhile, Grand Fenwick receives competing offers of defensive aid from each of the world's powers, in exchange for the weapon. Tully becomes smitten with Helen, who initially despises him for taking them but falls for his simple charm. Then Snippet and Mountjoy conspire to steal the bomb and return it to America, but Tully gives chase and retrieves it. The Secretary of Defense and Tully agree to terms: the knock-off wine will be taken off the market, Grand Fenwick will receive monetary aid from the US, Helen and her father will remain in Grand Fenwick, and so will the bomb: held by "the little countries of the world" as a weapon of last resort if the superpowers refuse to disarm. Checking the bomb for damage, Tully, Helen, and Dr. Kokintz find it was "a dud" all along, and leave it in the dungeon, conspiring to keep its impotence secret. However, after they leave, a mouse emerges from it, and it appears to rearm, sitting ready to explode if disturbed.
Cast
Peter Sellers as Duchess Gloriana XII/Prime Minister Count Rupert Mountjoy/Tully Bascombe
Stage rights to the book were bought in 1955 by Howard Dietz. Walter Shenson was doing publicity for Abandon Ship! in England in 1956 when given a copy of the novel by that film's star Tyrone Power. Shenson optioned the film rights in 1957 as his first independent production. He spent over a year trying to raise finance. He eventually obtained interest from Carl Foreman who had an arrangement to produce films for Columbia through his Highroad Films.
Changes from book
Liberties were taken in the film adaptation to display Peter Sellers' versatile comedy talents. The lead character of the book is the Duchess Gloriana XII, an attractive young royal in the manner of the young Queen Elizabeth II and Princess Grace of Monaco. In the film version, however, Peter Sellers plays the role as a parody of an elderly Queen Victoria, whilst his Mountjoy is a parody of Benjamin Disraeli. The Marseille and New York Harbor sequences were filmed in Southampton; the presence of the ocean liner there was a lucky coincidence. In addition, in the novel, an encounter with the New York Police Department leads to bloodshed that complicates peace negotiations; this does not appear in the film. Additionally, in the film, both Tully and Helen are with Dr. Kokintz when he discovers the bomb is a dud, and it is Tully who suggests that they keep that fact a secret; in the book Dr. Kokintz discovers the fact alone and apparently keeps it to himself.
Casting
The lead role went to Peter Sellers. The female lead went to Jean Seberg, who was then under contract to Columbia. At the time William Hartnell was well known for playing army sergeants, having played Sgt. Grimshaw in Carry on Sergeant in 1958 and Sgt. Maj. Percy Bullimore in the TV sitcom The Army Game.
Shooting
Title designer Maurice Binder added a mouse in an opening joke with the Columbia Pictures logo. One scene has diplomats playing a board game called Diplomacy, although the game more resembles Monopoly rather than the game Diplomacy.
Reception
The film did not perform up to expectations in the UK but was a surprise hit at the US box office. The Los Angeles Times said the film "laid an egg", but the New York Times offered a more positive review. On Rotten Tomatoes, which retrospectively collected a mix of contemporary and later reviews, the film has an approval rating of 90% based on reviews from 20 critics.
Adaptations
Television pilot
In 1964, Jack Arnold obtained exclusive television rights for The Mouse That Roared from Leonard Wibberley. He produced and directed a colour television pilot with ABC Television and Screen Gems called The Mouse That Roared, starring Sid Caesar as the Duchess, Mountjoy, and Tully, and co-starring Joyce Jameson, Sigrid Valdis, and Richard Deacon. However, the pilot was not picked up for production. It was filmed by Richard H. Kline.
Sequel
directed a film sequel, The Mouse on the Moon, adapted from Wibberley's 1962 novel The Mouse on the Moon.
Home video
The movie was released on VHS July 14, 1993. It was also released on DVD for the first time on July 8, 2003.
