Abstract: A method of manufacturing a sensing element, comprising bringing a first body in the form of an oil-free cross-linked matrix of flexible elastomeric material, the matrix containing electrically conductive particles, into contact with a second body of flexible elastomeric material that is electrically insulating and that contains an oil compatible with the elastomeric material of the first body, and allowing oil to migrate from the second to the first body so as to cause swelling of the first body, the migration continuing until a state of oil phase equalisation between the two bodies is reached.