Gas turbine engine

A gas turbine engine (1) has an annular bypass duct (4) defined between a fan nacelle (2) and a core fairing (3) through which fan air is discharged. One or more bifurcator members (5a-5i) are positioned inside the exit of the bypass duct (4) to bifurcate the air flow in the bypass duct around the bifurcator members (5a-5i) prior to exiting the bypass duct (4). The bifurcator members (5a-5i) modify the flow field of the air in the bypass duct radially and/or tangentially with respect to the axis of the annular bypass duct (4).