John Sullivan wrote the theme music for Only Fools and Horses when he wrote the first series, but the producers opted instead for an instrumental, saxophone-led tune composed by Ronnie Hazlehurst, who had also arranged the themes for other BBC sit-coms, such as Yes Minister and Last of the Summer Wine. However, Sullivan was unhappy with this, so for the second series he persuaded the BBC to use his own compositions instead, partly because the new lyrics would explain the obscure title, which had been the subject of viewers' questions to the BBC during the first series.
The first series was subsequently re-edited to use the new theme songs, though the first episode, "Big Brother", is still sometimes repeated with the original Hazlehurst music intact, as is the 1981 Christmas special. The current DVD release of Series One, however, replaces the theme music on all seven episodes. The original theme music is still used in the first episode during a montage in which Del unsuccessfully conducts business throughout Peckham whilst trying to sell stolen breifcases.
The lyrics to the established themes contain both slang and references to British culture, and describe elements of the show. The opening lyrics include "stick a pony in my pocket", pony being London slang for 25 pounds sterling; "fetch the suitcase from the van" and "where it all comes from is a mystery", all references to the Trotters' shady, cash-only business. It ends with the title lyric, "why do only fools and horses work?" The closing theme follows suit, describing the dubious goods that the Trotters specialise in, from "miles and miles of carpet tiles" to "Trevor Francis tracksuits"; Francis was an English football player during the 1970s and 1980s. These are "from a mush in Shepherd's Bush"; mush is slang for a man whose name is unknown and Shepherd's Bush is a West London district.The line "no income tax, no VAT" summarises their outlook, before closing with the refrain "God bless Hooky Street". Hooky is British slang for something stolen or which has been acquired illegally. The images peeling away was conceived as a metaphor for the Trotters' lifestyle
Both songs are performed by Sullivan, and not – as is sometimes thought – by Nicholas Lyndhurst.Sullivan had intended for Chas & Dave to sing it, since they were an act associated with Cockney-style music, but they were unavailable having just recorded a hit record with "Ain't No Pleasing You", so he was persuaded to do it himself by Ray Butt.The new theme was also arranged by Hazlehurst. Chas & Dave did later contribute to the show, performing "Down to Margate", the closing credits song for "The Jolly Boys' Outing".
The opening credits see images of the three principal actors peel on and off the screen sequentially like adhesive labels. These appear over a background of still photographs of everyday life in South London, including a used car lot and a tower block. The sequence was conceived by graphic designer, Peter Clayton, as a "metaphor for the vagaries of the Trotters' lifestyle", whereby money was earned and quickly lost again. The action was shot manually frame by frame, and took around six weeks to complete.
As the series progressed, the sequence was occasionally updated with new footage, but it only ever featured Del, Rodney and either Grandad or Uncle Albert. The 2001–2003 trilogy featured just Del and Rodney. In total, the shots of Del and Rodney were updated three times during the series' run to reflect their ageing, whilst Grandad and Uncle Albert only ever received one version each during their run. The 2001-2003 Christmas specials used the same titles sequences but rendered for broadcast in the now standard 16:9 ratio widescreen.
The closing credits for the programme varied series by series. The first series used peeling labels featuring the names of the cast and crew, mirroring the opening sequence, but these had to be updated with every new episode, making the process very time-consuming; from the second series the credits switched to a standard rolling format. Towards the end of the run they settled on a uniform style with the typeface Dom Casual scrolling against a freeze frame of the final scene which faded to a plain black background. Despite strict BBC crediting guidelines in place by the time the most recent episodes screened, the programme was able to enjoy unedited closing credits and the full version of the theme song.