A filter assembly for removing material that is entrained in a gas stream. The filter assembly comprises a filter element comprising a wall of a filtration medium which defines a hollow space, for a gas stream to flow from the space through the wall to be filtered. The wall includes a filtration layer, and a drainage layer located outside the filtration layer in which liquid separated from the gas stream can collect. The filter element comprises first and second end caps at opposite ends of the wall, the first end cap including an inlet for a gas stream to be supplied to the space within the wall. The filter assembly further comprises a housing in which the filter element can be received when in use. The housing has an inlet port for a gas stream to flow into the housing which communicates with the inlet in the first end cap, and an outlet port through which gas which has passed through the filtration medium can leave the housing. The drainage layer extends over at least a part of the external surface of the second end cap between the second end cap and the housing and the part of the drainage layer between the second end cap and the housing is locally compressed by at least one longitudinally extending fin.