The b → sγ transition proceeds through flavour changing neutral currents, and thus is particularly sensitive to the effects of new physics. An overview of the method to measure the photon polarisation at the LHCb experiment via an angular analysis of B → K*e+e− at low q2 is presented. The status of the B → K*μ+μ− analysis with 309 pb−1 of pp collisions at √s = 7 TeV at LHCb is also given.