  We have measured the linear polarisation of hard X-ray emission from the Crab
in a previously unexplored energy interval, 20-120 keV. The introduction of two
new observational parameters, the polarisation fraction and angle stands to
disentangle geometrical and physical effects, thereby providing information on
the pulsar wind geometry and magnetic field environment. Measurements are
conducted using the PoGOLite Pathfinder - a balloon-borne polarimeter.
Polarisation is determined by measuring the azimuthal Compton scattering angle
of incident X-rays in an array of plastic scintillators housed in an
anticoincidence well. The polarimetric response has been characterised prior to
flight using both polarised and unpolarised calibration sources. We address
possible systematic effects through observations of a background field. The
measured polarisation fraction for the integrated Crab light-curve is
($18.4^{+9.8}_{-10.6}$)%, corresponding to an upper limit (99% credibility) of
42.4%, for a polarisation angle of ($149.2\pm16.0)^\circ$.
