Natural gas is processed to generate longer-chain hydrocarbons, the process comprising subjecting the gas to steam reforming to generate a mixture of carbon monoxide and hydrogen, and then subjecting this mixture to Fischer-Tropsch synthesis. The Fischer-Tropsch synthesis is performed at an elevated temperature above 230.degree. C. and with a gas hourly space velocity greater than 10 000 hr.sup.-1 so as to achieve a selectivity to the production of C5+ hydrocarbons that is less than 65%. The resulting liquid product can be used as a vehicle fuel, while the tail gases may be used to generate electricity.