A gas turbine engine including a support structure for attaching the engine to an aircraft pylon having a front connection face; wherein the engine further includes: an engine core comprising a turbine (17, 19), a compressor (14, 15), and a core shaft (26, 27) connecting the turbine (17, 19) to the compressor (14, 15), and a core casing surrounding the engine core; wherein the support structure includes: an engine-side interface member positioned outwardly of and radially spaced from the core casing, the engine-side interface member extending circumferentially around a top half of the core casing from a bottom end of the engine-side interface member on one side of the core casing to an opposite bottom end on the opposite side of the core casing, a pylon-side interface member configured to join to the front connection face and interfacing to the engine-side interface member, the pylon-side interface member also extending circumferentially around the top half of the core casing, and a top V-shaped connection formation positioned above the engine core and pair of side V-shaped connection formations positioned on opposite lateral sides of the engine core, each V-shaped connection formation (37, 39) being formed by a pair of connection members meeting at a vertex, the vertex of the top V-shaped connection formation joining to the top of the engine-side interface member, the vertices of the side V-shaped connection formations respectively joining to the bottom ends of the engine-side interface member, and the connection members extending forwardly from their respective vertices to join to respective front fixation points at the core casing; and wherein the engine-side interface member and the pylon-side interface member are joined by plural circumferentially spaced connective links (45, 46; 45, 46') configured so as to transfer roll torques from the engine to the pylon. an engine core comprising a turbine (17, 19), a compressor (14, 15), and a core shaft (26, 27) connecting the turbine (17, 19) to the compressor (14, 15), and a core casing surrounding the engine core; wherein the support structure includes: an engine-side interface member positioned outwardly of and radially spaced from the core casing, the engine-side interface member extending circumferentially around a top half of the core casing from a bottom end of the engine-side interface member on one side of the core casing to an opposite bottom end on the opposite side of the core casing, a pylon-side interface member configured to join to the front connection face and interfacing to the engine-side interface member, the pylon-side interface member also extending circumferentially around the top half of the core casing, and a top V-shaped connection formation positioned above the engine core and pair of side V-shaped connection formations positioned on opposite lateral sides of the engine core, each V-shaped connection formation (37, 39) being formed by a pair of connection members meeting at a vertex, the vertex of the top V-shaped connection formation joining to the top of the engine-side interface member, the vertices of the side V-shaped connection formations respectively joining to the bottom ends of the engine-side interface member, and the connection members extending forwardly from their respective vertices to join to respective front fixation points at the core casing; and wherein the engine-side interface member and the pylon-side interface member are joined by plural circumferentially spaced connective links (45, 46; 45, 46') configured so as to transfer roll torques from the engine to the pylon. an engine-side interface member positioned outwardly of and radially spaced from the core casing, the engine-side interface member extending circumferentially around a top half of the core casing from a bottom end of the engine-side interface member on one side of the core casing to an opposite bottom end on the opposite side of the core casing, a pylon-side interface member configured to join to the front connection face and interfacing to the engine-side interface member, the pylon-side interface member also extending circumferentially around the top half of the core casing, and a top V-shaped connection formation positioned above the engine core and pair of side V-shaped connection formations positioned on opposite lateral sides of the engine core, each V-shaped connection formation (37, 39) being formed by a pair of connection members meeting at a vertex, the vertex of the top V-shaped connection formation joining to the top of the engine-side interface member, the vertices of the side V-shaped connection formations respectively joining to the bottom ends of the engine-side interface member, and the connection members extending forwardly from their respective vertices to join to respective front fixation points at the core casing; and wherein the engine-side interface member and the pylon-side interface member are joined by plural circumferentially spaced connective links (45, 46; 45, 46') configured so as to transfer roll torques from the engine to the pylon.