A casing assembly for a gas turbine engine, the casing assembly comprising: a casing comprising a slot defined by a front surface and a rear surface, the front surface and the rear surface being spaced apart by an axial casing gap; and a plurality of stator vanes each comprising a platform and at least one aerofoil (38, 40) extending from the platform, the platform being received within the slot and having an axial length and a circumferential length (w); wherein the circumferential lengths of the platforms define a total circumferential length which is less than the circumference of the casing at an outer radial surface of the platforms and so defines a circumferential clearance; wherein the axial length of each of the platforms is less than the axial casing gap and so defines an axial clearance; wherein the circumferential and axial clearances allow the platforms of the stator vanes to rotate within the slot, with rotation of the platforms from an unrotated position reducing the circumferential and axial clearance; wherein the front and rear surfaces of the casing and the platforms of the stator vanes are configured such that rotation of the platforms from the unrotated position entirely consumes the circumferential clearance so that adjacent platforms abut against one another and prevent further rotation of the platforms while maintaining an axial clearance, the casing assembly characterised in that the front and rear surfaces of the casing and the platforms of the stator vanes are configured such that the following inequality is satisfied: 90 − sin − 1 C N sin 90 + θ C N + g N + θ < tan − 1 C N − L tan ⁢ θ L − cos − 1 G L 2 + C N − L tan θ 2 where θ represents a scarf angle of the platforms of the stator vanes, N represents the number of stator vanes received within the slot, L represents the axial lengths of the platforms, C represents the circumference of the casing at an outer radial surface of the platforms, g represents the total circumferential clearance when the platforms are in their unrotated positions, and G represents the axial casing gap. a casing comprising a slot defined by a front surface and a rear surface, the front surface and the rear surface being spaced apart by an axial casing gap; and a plurality of stator vanes each comprising a platform and at least one aerofoil (38, 40) extending from the platform, the platform being received within the slot and having an axial length and a circumferential length (w); wherein the circumferential lengths of the platforms define a total circumferential length which is less than the circumference of the casing at an outer radial surface of the platforms and so defines a circumferential clearance; wherein the axial length of each of the platforms is less than the axial casing gap and so defines an axial clearance; wherein the circumferential and axial clearances allow the platforms of the stator vanes to rotate within the slot, with rotation of the platforms from an unrotated position reducing the circumferential and axial clearance; wherein the front and rear surfaces of the casing and the platforms of the stator vanes are configured such that rotation of the platforms from the unrotated position entirely consumes the circumferential clearance so that adjacent platforms abut against one another and prevent further rotation of the platforms while maintaining an axial clearance,