A method of removing sulfur from a fuel supply stream for a fuel cell (1), which method comprises: (a) hydrogenating the fuel supply stream (1) by contacting it with a hydrogenation catalyst in the presence of hydrogen to convert sulfur-containing compounds in the fuel supply stream (1) into hydrogen sulfide; (b) removing the hydrogen sulfide to produce a desulfurised fuel stream; and (c) pre-reforming the desulfurised fuel stream to produce a fuel cell feed stream, wherein a portion of the fuel cell feed stream is processed to increase its hydrogen content to produce a hydrogen-enriched fuel stream which is used in step (a) as a source of hydrogen to hydrogenate the fuel supply stream (1).