The Fifth Rutle is an informal title that various commentators in the press and entertainment industry have applied to persons who were at one point a member of the Rutles, or had a strong association with the "Pre-Fab Four" (Nasty, Dirk, Stig, and Barry) during the group's existence.
Leppo has been called the fifth Rutle. The original bassist of the five-member Rutles, he played with the band primarily during their days as a club act in Hamburg, Germany. He didn't know how to play an instrument, but he did knew how to have a good time. Leppo was last seen crawling into a trunk with a small German Fräulein and was never heard from again.
The original drummer for The Rutles, Kevin played with the band from 1959-1961. He could play drums but only in a poor manner. He was replaced when Barry was discovered in the back of their van, at which point he replaced Kevin in the group.
Tony Sheridan was another artist who performed with The Rutles while they were in Hamburg, although due to Leppo also being present this would perhaps actually make him a "Sixth Rutle." Along with playing together at Der Rat Keller, the sextet did one recording session together which resulted in the single "My Ronnie"/"Death Cab for Cutie".
Leggy Mountbatten, the band's manager from 1961 until his acceptance of a teaching post in Australia in 1967, was instrumental in The Rutles' rise to global fame. Mountbatten "discovered" the band in Liverpool.
Archie Macaw, the Rutles' producer, helped in the Pre-Fab Four songs. He notably created all of the instrumental music for the Yellow Submarine Sandwich film, and later helped remaster some of the songs for Archaeology and Lunch. Upon his passing, Dirk McQuickly stated, "If anyone earned the title of the fifth Rutle, it was Archie".
Bill Murray the K
Bill Murray the K was a radio disk jockey who became an early supporter of the Rutles, helping to kickstart Rutlemania in the United States. Upon meeting the band, he spent some time around him and eventually gained the nickname "the Fifth Rutle." He would promote himself as this on his radio show, but would later come to regret this.
Eric Manchester was the press officer for the Rutles who worked for Rutle Corps from 1968 through 1970. A close associate of the band, he served as their negotiator to the press and also designed numerous promotional campaigns. He became instrumental to the restoration attempts of Archaeology, both being the man who had buried the missing tapes and the one who helped dig them up. Stig O'Hara once referred to him as one of the few men who earned the title of the Fifth Rutle.
Rutling Orange Peel
Rutling Orange Peel claimed to have crafted the Rutles' entire catalog, which could potentially make him the band's fifth creative member.
Dirk, Nasty, Stig or Barry
If Ruttling Orange Peel really did invent the band's music, another argument is that he would really be the first Rutle. This would mean that either Dirk, Nasty, Stig or Barry would be the fifth Rutle, depending on which order they would be listed. Most believe this would make Barry Wom the Fifth Rutle.
The Replacement Stig
If one believes the Stig is dead conspiracy, in which Stig was replaced by a look-alike or wax mannequin, then logically the fake Stig (or "Ftig") would be the Fifth member of the band, meaning the members would be: Dirk, Nasty, Stig, Barry and Ftig.
The Replacement Dirk
If one believes the Dirk is deaf conspiracy theory, that Dirk had gone deaf early into the band's history and had been dubbed by another performer during his entire career, then the Fifth Rutle would logically be whoever was dubbing Dirk's voice. On the other hand, if Dirk never performed on any Rutle songs, this would mean he was never really a band member and there still were only four members of the band.
The Replacement Barry
Martini McQuickly was Dirk's wife, who he would later form Punk Floyd with. Martini would arrive to some Beatle recording sessions, to the protests of other members, and would not sing. However, Dirk has called her essential to his creative process on Shabby Road.
Martini McQuickly's dog
When Martini would come to the recording studio, she would sometimes bring her dog Molly, much to the protest of the other members. Recordings of Molly barking would be used on several songs, and can be heard specifically on Archaeology. In 2003, Barry Wom stated, "If any person ever was worthy of being the Fifth Rutle, it was Dirk's dog."
Chef Percy was a close associate of the Rutles in their 1968 film Yellow Submarine Sandwich. In the film, he creates the Submarine Sandwich and gathers the band to fight the Blue-Headed Sharks. Percy spends a considerable amount of time with the four, even during musical numbers. However, he is fictional.
Salman Rushdie is the biggest Rutles fan in the world, and is thus considered by some to be the Fifth Rutle.
Rutling Ken Thornton
Rutling Ken Thornton was a performer who joined The Rutles during their touring seasons following Archaeology. Playing lead guitar and vocals, he is one of the longest-lasting members of the band outside of the main four. He is featured in the live album The Rutles: Live+Raw and the bootleg recording A Hoot and Some Tea Back in '03.
A recording of a screaming goat, uploaded to YouTube in April 2012  was featured in live performances. The goat was credited as a performer on The Rutles: Live+Raw. In 2019, Ron Nasty stated "if anyone has earned the title of the Fifth Rutle, it was the screaming goat we found online."
In 2006, Time Magazine began an investigation into who the official Fifth Rutle was. At the end of their research, they released a special issue revealing their conclusion: the reader was the most important part of the band's legacy, and thus they were the Fifth Rutle. The cover featured a piece of reflective material which, when looked at head-on, showed one's reflection.
Although, strictly speaking, it is possible to interpret that you are really the 24th Rutle.