Wikipedia
LeRoc is a form of Modern Jive, a dance style that was derived in the 1980s, from dances including Swing, Lindy Hop and Rock and Roll, the main innovation being to simplify the footwork.
According to the particular teacher, it may incorporate elements of other dance styles including Salsa and Tango.
Both Ceroc and LeRoc originally evolved together in London during the Jive revival in the early 1980s, with dancers often being a member of both clubs. However, when James Cronin chose to trademark the word "Ceroc", and to run the Ceroc club as a franchised business, the members of the LeRoc club decided not to run theirs for the potential income, preferring to concentrate on perfecting the dance. This means that today, many unrelated Modern Jive organisations are free to use the term "LeRoc" in their names as it remains a generic term.
"The LeRoc Modern Jive Federation" is a non-profit federation of independent dance teachers that was set up in 1991, but it is not mandatory to join. It offers advantages (such as membership of the United Kingdom Alliance of Professional Teachers of Dancing and Kindred Arts (UKA)) to its members.
It is said that the dance style came from France, where Swing / Rock and Roll dancing had not been so suppressed by the onslaught of Disco. Le Roc is French for The Rock (and Roll).
Despite the supposed origins in France, there is currently very little Modern Jive danced in France.