A container having a container body to hold pressurised liquid and a neck with a closure engaged on said neck; - wherein said container neck and said closure are both formed of yieldable polymer; - wherein the neck has a mouth providing access to the interior of the container body; - wherein the closure has an end wall and a skirt; - wherein the skirt is provided with internal screw threads which co-operate with external screw threads on the neck to hold the closure on the container body; - wherein the internal screw threads and the external screw threads each comprise complete circumferential turns; - wherein each of the screw threads (23, 24) has a root (26, 30) where the respective screw thread (23, 24) is joined to the neck or skirt and an outer extremity (27, 31) remote from the neck or skirt; - wherein each of the screw threads (23, 24) has a proximal face (28, 32) closest to the container body and an opposite distal face (29, 33), each of said proximal and distal faces extending from the root (26, 30) of the respective screw thread to the outer extremity (27, 31) thereof; - wherein a pressure seal is formed between the mouth of the neck and the end wall of the closure when the closure is screwed onto the neck whereby the pressurised liquid is retained within the container; characterised in that the proximal face of the external screw threads and/or the distal face of the internal screw threads is formed with transverse venting channels extending from the base (26, 30) of the respective screw threads to the outer extremity thereof (27, 31), and wherein the the distal face of the external screw threads and/or the proximal face of the internal screw threads opposite each of the venting channels is substantially continuous. - wherein said container neck and said closure are both formed of yieldable polymer; - wherein the neck has a mouth providing access to the interior of the container body; - wherein the closure has an end wall and a skirt; - wherein the skirt is provided with internal screw threads which co-operate with external screw threads on the neck to hold the closure on the container body; - wherein the internal screw threads and the external screw threads each comprise complete circumferential turns; - wherein each of the screw threads (23, 24) has a root (26, 30) where the respective screw thread (23, 24) is joined to the neck or skirt and an outer extremity (27, 31) remote from the neck or skirt; - wherein each of the screw threads (23, 24) has a proximal face (28, 32) closest to the container body and an opposite distal face (29, 33), each of said proximal and distal faces extending from the root (26, 30) of the respective screw thread to the outer extremity (27, 31) thereof; - wherein a pressure seal is formed between the mouth of the neck and the end wall of the closure when the closure is screwed onto the neck whereby the pressurised liquid is retained within the container; characterised in that the proximal face of the external screw threads and/or the distal face of the internal screw threads is formed with transverse venting channels extending from the base (26, 30) of the respective screw threads to the outer extremity thereof (27, 31), and wherein the the distal face of the external screw threads and/or the proximal face of the internal screw threads opposite each of the venting channels is substantially continuous.