A vehicle pressure sensing system, comprising: a pressure sensor; a housing defining an internal space which is in fluid communication with the pressure sensor so that the pressure of gas within the internal space can be sensed by the pressure sensor; a first connection arrangement, allowing connection of the sensor to a substantially enclosed and compressible sensing member, so that variations in pressure in the sensing member are communicated to the internal space; and a venting arrangement, allowing gas communication between the internal space and the surrounding atmosphere, wherein the venting arrangement comprises: a passage comprising or leading to an exit port; a filter arrangement having an inner end and an outer end and being positioned within the passage so that it partially occludes the passage, the filter arrangement having at least one flow path formed therein passing from the inner end to the outer end but preventing or substantially preventing the passage of water through the filter arrangement and a filter housing and a filter element (8, 20, 23, 25, 27, 29, 35,45,47,49,52,81) wherein the filter element fits within the filter housing wherein the filter housing; the filter element has an inner surface; the filter element has an outer surface; in use, the filter element is positioned within the filter housing so that there is a close fit between the inner surface of the filter housing and the outer surface of the filter element; and the flow path comprises a channel (22, 24, 26, 28, 30,41) formed in the inner surface of the filter housing or in the outer surface of the filter element. a pressure sensor; a housing defining an internal space which is in fluid communication with the pressure sensor so that the pressure of gas within the internal space can be sensed by the pressure sensor; a first connection arrangement, allowing connection of the sensor to a substantially enclosed and compressible sensing member, so that variations in pressure in the sensing member are communicated to the internal space; and a venting arrangement, allowing gas communication between the internal space and the surrounding atmosphere, wherein the venting arrangement comprises: a passage comprising or leading to an exit port; a filter arrangement having an inner end and an outer end and being positioned within the passage so that it partially occludes the passage, the filter arrangement having at least one flow path formed therein passing from the inner end to the outer end but preventing or substantially preventing the passage of water through the filter arrangement and a filter housing and a filter element (8, 20, 23, 25, 27, 29, 35,45,47,49,52,81) wherein the filter element fits within the filter housing wherein the filter housing; the filter element has an inner surface; the filter element has an outer surface; in use, the filter element is positioned within the filter housing so that there is a close fit between the inner surface of the filter housing and the outer surface of the filter element; and the flow path comprises a channel (22, 24, 26, 28, 30,41) formed in the inner surface of the filter housing or in the outer surface of the filter element. a passage comprising or leading to an exit port; a filter arrangement having an inner end and an outer end and being positioned within the passage so that it partially occludes the passage, the filter arrangement having at least one flow path formed therein passing from the inner end to the outer end but preventing or substantially preventing the passage of water through the filter arrangement and a filter housing and a filter element (8, 20, 23, 25, 27, 29, 35,45,47,49,52,81) wherein the filter element fits within the filter housing wherein the filter housing; the filter element has an inner surface; the filter element has an outer surface; in use, the filter element is positioned within the filter housing so that there is a close fit between the inner surface of the filter housing and the outer surface of the filter element; and the flow path comprises a channel (22, 24, 26, 28, 30,41) formed in the inner surface of the filter housing or in the outer surface of the filter element.