A compressor of a gas turbine engine comprises blades 2, 4 provided on blade platforms 8, 12 of a rotor. Stator vanes 20 lie between the blades 2, 4 and are connected to a vane support structure 22. Sealing rings 38 are secured to the vane support structure 22 to restrict air flow into stator wells 36 on each side of the vane support structure 22. The sealing rings 38 are made from a flexible material so that they deflect on installation of the vane support structure 22 in a direction radially inwards between the adjacent blade platforms 8, 12.