According to the present invention, there is provided an organophosphine ligand comprising a phosphabicyclohydrocarbyl group in which the phosphorus atom is further substituted with a hydrocarbyl or heterohydrocarbyl moiety containing at least one branch at the β-carbon position. The present invention also provides a catalytic composition for the hydroformylation of an ethylenically unsaturated compound, said catalytic composition comprising i) a source of Group VIII metal cations; and ii) the above ligand. Furthermore, the present invention also provides a process for the hydroformylation of an ethylenically unsaturated compound, said process comprising contacting the ethylenically unsaturated compound with carbon monoxide and hydrogen in the presence the above catalytic composition.