We present FLEX, an instrument to demonstrate the power of fibre Bragg grating OH suppression. This ground breaking technology promises great gains in sensitivity for near infrared instrumentation and the time is now right for a pioneer instrument to prove the effectiveness of the technique. Our proposal is for an adaptive optics fed integral field unit for an 8 metre class telescope. We envisage a 61 element IFU with 0.22" sampling and a 2.2" field of view. J and H-band OH suppression units would cleanly suppress the atmospheric emission lines,effectively lowering the sky background by 3 or 4 magnitudes respectively. The capabilities of FLEX will make it ideal for deep Epoch of Reionisation studies, as well as studies of star formation at z ̃1-4. To enable rapid and economical deployment FLEX would use an existing near infrared spectrograph with R ≈ 1000 and employ facility adaptive optics.