A vacuum cleaner incorporating a cyclone separation device comprises a cylindrical cyclone chamber having a tubular side wall in the form of a filter. An auger is mounted within the chamber for rotation about the longitudinal axis thereof, the auger having a vane which extends along the chamber in a first helical direction. In use, the auger is rotated in a direction opposite to said helical direction so that separated dirt and dust is driven to a collection region at the bottom of the chamber and compacted. The collection region preferably expands during use to increase the capacity thereof. A vacuum cleaner in accordance with the invention has to be emptied less regularly and any risk of dust re-entrainment is reduced.