A gas turbine engine comprising a fan, a bypass duct positioned downstream of the fan and defined by an inner casing and an outer casing, a series of outlet guide vanes arranged downstream of the fan, the outlet guide vanes extending between the inner casing and the outer casing of the bypass duct; and a bifurcation positioned downstream of the outlet guide vanes and extending between the inner casing and the outer casing. The bifurcation comprises a leading edge, and the leading edge of the bifurcation is shaped so as to protrude axially forward by a varying distance from the inner casing to the outer casing so as to improve uniformity of a static pressure field formed, in use, immediately upstream of the bifurcation.