A feed stream, comprising hydrogen sulphide (H2S), carbon dioxide (CO2), hydrogen (H2) and, optionally, carbon monoxide (CO), is separated into at least a CO2 product stream and an H2 or H2 and CO product stream. The stream is separated using a pressure swing adsorption system, an H2S removal system and a further separation system, which systems are used in series to separate the stream. The method has particular application in the separation of a sour (i.e. sulphur containing) syngas, as for example produced from the gasification of solid or heavy liquid carbonaceous feedstock.