A bidirectional downhole fluid flow control system comprising: a plurality of injection flow control components having direction dependent flow resistance; and a plurality of production flow control components having direction dependent flow resistance; wherein, injection fluid flow (338,340) experiences a greater flow resistance through the production flow control components than through the injection flow control components; and wherein, production fluid flow (342,344) experiences a greater flow resistance through the injection flow control components than through the production flow control components; the downhole fluid flow control system being characterised in that: the injection flow control components further comprises two stage flow control components including, in series, a first vortex diode stage and a second vortex diode stage, each of the first and second stages (306,308) of the injection flow control components having a central inlet port (310,316) and a radial outlet port (314,320), wherein the radial outlet port of the first stage is in fluid communication with the central inlet port of the second stage of the injection flow control components; and the production flow control components further comprises two stage flow control components including, in series, a first vortex diode stage and a second vortex diode stage, each of the first and second stages (322,324) of the production flow control components having a central outlet port (326,332) and a radial inlet port (330,336), wherein the central outlet port of the first stage is in fluid communication with the radial inlet port of the second stage of the production flow control components, wherein, the production flow control components are in parallel with the injection flow control components. a plurality of injection flow control components having direction dependent flow resistance; and a plurality of production flow control components having direction dependent flow resistance; wherein, injection fluid flow (338,340) experiences a greater flow resistance through the production flow control components than through the injection flow control components; and wherein, production fluid flow (342,344) experiences a greater flow resistance through the injection flow control components than through the production flow control components; the downhole fluid flow control system being characterised in that: the injection flow control components further comprises two stage flow control components including, in series, a first vortex diode stage and a second vortex diode stage, each of the first and second stages (306,308) of the injection flow control components having a central inlet port (310,316) and a radial outlet port (314,320), wherein the radial outlet port of the first stage is in fluid communication with the central inlet port of the second stage of the injection flow control components; and the production flow control components further comprises two stage flow control components including, in series, a first vortex diode stage and a second vortex diode stage, each of the first and second stages (322,324) of the production flow control components having a central outlet port (326,332) and a radial inlet port (330,336), wherein the central outlet port of the first stage is in fluid communication with the radial inlet port of the second stage of the production flow control components, wherein, the production flow control components are in parallel with the injection flow control components. the injection flow control components further comprises two stage flow control components including, in series, a first vortex diode stage and a second vortex diode stage, each of the first and second stages (306,308) of the injection flow control components having a central inlet port (310,316) and a radial outlet port (314,320), wherein the radial outlet port of the first stage is in fluid communication with the central inlet port of the second stage of the injection flow control components; and the production flow control components further comprises two stage flow control components including, in series, a first vortex diode stage and a second vortex diode stage, each of the first and second stages (322,324) of the production flow control components having a central outlet port (326,332) and a radial inlet port (330,336), wherein the central outlet port of the first stage is in fluid communication with the radial inlet port of the second stage of the production flow control components, wherein, the production flow control components are in parallel with the injection flow control components.