Abstract: Described is a leaf seal for sealing between a static component and a relatively rotating component having an axis of rotation, the leaf seal defining axially separated higher pressure upstream and lower pressure downstream areas within the static component when in use, the leaf seal comprising: a plurality of leaf elements having: a root end for attachment to the static component; a free end for wiping contact with the rotating component; an upstream edge extending from the root end to the free end; and, a downstream edge extending from the root end to the free end, wherein the leaf element width between the upstream edge and downstream edge at the root end is a, and width between the upstream edge and the downstream edge at the free end is b, where b<0.5?.