A filter assembly which comprises a filter element for filtering a fluid, and a mount having at least one port (24, 26), each of the filter element and the mount having interengaging connection formations (120, 230) by which the filter element and the mount can be detachably connected to one another, and the mount defining a flow path for fluid to flow between the port and the filter element when the filter element is connected to the mount, in which the mount includes a link element (104, 500) which can slide relative to the mount between a retracted position and a deployed position, the link element having one of a lug and an inclined ramp surface which is arranged around an axis, and the filter element having the other of the lug and the inclined ramp surface, and in which the lug and the ramp surface form a cam drive in which the lug is capable of engaging the inclined ramp surface as the filter element and the mount are brought together for assembly, and of sliding along the inclined ramp surface when the filter element is rotated relative to the mount to cause the link element to be drawn out of the mount towards its deployed position, and in which the filter element and the mount are arranged so that they are brought together by moving the filter element in a first direction relative to the mount, the lug and the ramp surface arranged so that the link element moves from the retracted position to the deployed position in a second direction which is opposite to the first direction, the link element moving axially away from the mount to the deployed position, and in which the connection formations on the mount are provided on the link element, and the connection formations on the mount and the filter element are unable to engage one another when the link element is in its retracted position. in which the mount includes a link element (104, 500) which can slide relative to the mount between a retracted position and a deployed position, the link element having one of a lug and an inclined ramp surface which is arranged around an axis, and the filter element having the other of the lug and the inclined ramp surface, and in which the lug and the ramp surface form a cam drive in which the lug is capable of engaging the inclined ramp surface as the filter element and the mount are brought together for assembly, and of sliding along the inclined ramp surface when the filter element is rotated relative to the mount to cause the link element to be drawn out of the mount towards its deployed position, and in which the filter element and the mount are arranged so that they are brought together by moving the filter element in a first direction relative to the mount, the lug and the ramp surface arranged so that the link element moves from the retracted position to the deployed position in a second direction which is opposite to the first direction, the link element moving axially away from the mount to the deployed position, and in which the connection formations on the mount are provided on the link element, and the connection formations on the mount and the filter element are unable to engage one another when the link element is in its retracted position.