In order to implement a standard free PIGE analysis of phosphorus, the cross section of the reaction 31P(p,pγ1-0)31P, γ1-0=1266.1keV was measured for the proton energy range 2.6–4 MeV, with energy steps ranging from 1 keV on resonances to 10 keV off resonance. This data provides additional information in relation to previous works on this reaction, as a more detailed and extended (in energy) measurement was mad...