A removable seal 10 is provided for positioning in a bore 14 around an element which, in use, passes therethrough. The seal comprises: a cylindrical outer sleeve 13 having an axial bore, the sleeve 13 having at least one engagement portion for engaging, in use, with an internal surface of the bore 14; and a sealing element 17 mounted on the cylindrical outer sleeve 13 for, in use, extending into the axial bore 14 to seal around the element passing therethrough.