A method for producing a low sulphur containing fuel from a hydrocarbon feed having from 10 to 80 ppm of sulphur is disclosed. The method comprises contacting a hydrocarbon stream comprising at least one olefin having from 2 to 6 carbon atoms and at least one paraffin having from 4 to 6 carbon atoms with an ionic liquid catalyst and a halide containing additive in an alkylation reaction zone under alkylating conditions to produce a fuel having sulphur content up to 10 ppm.