A method of producing hydrogen for a fuel cell from a hydrocarbon fuel composition, by providing a hydrocarbon fuel composition, which is obtained by contacting a liquid hydrocarbon feed comprising an alkylating agent with an acidic catalyst, under conditions effective to alkylate at least a portion of the hydrocarbon feed; converting the hydrocarbon fuel composition into hydrogen; and optionally, introducing the hydrogen produced into a fuel cell. In a preferred embodiment the liquid hydrocarbon feed further comprises sulphur-containing impurities, at least a portion of which are alkylated during the alkylation step.