Until now, the Cabibbo Kobayashi Maskawa matrix element, |V cb |, has always been measured in B decays, i.e. at an energy scale q b ∼ m b 2 , far below the weak scale. We consider here the possibility of measuring it close to the weak scale, at q W ∼ m W , in top decays at the Large Hadron Collider (LHC). Our proposed method would use data from the LHC experiments in hadronic top decays t → bW → bbc, tagged by the semileptonic decay of the associated top. We estimate the uncertainty of such a measurement, as a function of present and potential future experimental jet flavour-tagging performances, and conclude that first measurements using the data collected during 2016 -2018 could yield a fractional error on |V cb | of order 7% per experiment. We also give projected performances at higher luminosities, representative of LHC Run 3 and HL-LHC.