A gas turbine engine comprising: at least two compressor rotors (44, 52), including a first lower pressure compressor rotor and a second higher pressure compressor rotor; at least two corresponding air taps (86, 92, 98), including: a low tap for tapping low pressure compressor air from a location downstream of a first stage of the lower pressure compressor rotor, and upstream of a first stage of the higher pressure compressor rotor; and a high tap (86, 92) to tap air downstream of said first stage of said higher pressure compressor rotor; and an air handling system to selectively communicate both said low tap and said high tap (86, 92) to an air use destination, wherein the engine is configured such that air is selectively supplied from the low tap to the air handling system at a high power operation and from said high tap (86, 92) to the air handling system at a low power operation; characterised in that: a fan rotor is driven through a gear reduction by a fan drive turbine, wherein said fan drive turbine further drives said lower pressure compressor rotor; and said high tap (86, 92) includes at least two different tap locations, wherein the engine is configured such that the two different tap locations are selectively utilized at different operational conditions. at least two compressor rotors (44, 52), including a first lower pressure compressor rotor and a second higher pressure compressor rotor; at least two corresponding air taps (86, 92, 98), including: a low tap for tapping low pressure compressor air from a location downstream of a first stage of the lower pressure compressor rotor, and upstream of a first stage of the higher pressure compressor rotor; and a high tap (86, 92) to tap air downstream of said first stage of said higher pressure compressor rotor; and a low tap for tapping low pressure compressor air from a location downstream of a first stage of the lower pressure compressor rotor, and upstream of a first stage of the higher pressure compressor rotor; and a high tap (86, 92) to tap air downstream of said first stage of said higher pressure compressor rotor; and an air handling system to selectively communicate both said low tap and said high tap (86, 92) to an air use destination, wherein the engine is configured such that air is selectively supplied from the low tap to the air handling system at a high power operation and from said high tap (86, 92) to the air handling system at a low power operation; characterised in that: a fan rotor is driven through a gear reduction by a fan drive turbine, wherein said fan drive turbine further drives said lower pressure compressor rotor; and said high tap (86, 92) includes at least two different tap locations, wherein the engine is configured such that the two different tap locations are selectively utilized at different operational conditions. a fan rotor is driven through a gear reduction by a fan drive turbine, wherein said fan drive turbine further drives said lower pressure compressor rotor; and said high tap (86, 92) includes at least two different tap locations, wherein the engine is configured such that the two different tap locations are selectively utilized at different operational conditions.