A process (10) for the preparation and conversion of synthesis gas includes reforming a feed gas (34) comprising methane in a reforming stage (18) to produce synthesis gas (46) which includes hydrogen and carbon monoxide. Some of the hydrogen and carbon monoxide is converted to a Fischer-Tropsch product (48) in a Fischer-Tropsch hydrocarbon synthesis stage (24). A tail gas (52), including unreacted hydrogen and carbon monoxide, methane and carbon dioxide, is separated from the Fischer-Tropsch product (48). In a tail gas treatment stage (28,30), the tail gas (52) is treated by reforming the methane in the tail gas (52) with steam (66) and removing carbon dioxide to produce a hydrogen rich gas (56). The tail gas treatment stage (28,30) may be either a combined tail gas treatment stage (28,30) or a composite tail gas treatment stage. The carbon dioxide from the tail gas treatment stage (28,30) is fed to the reforming stage (18).