Charmless charged two-body b-hadron decays, with kaons and pions in the final state, are an optimal test of the Standard Model validity. Indeed these decays receive important contributions from loop-level processes making the $C\!P$ asymmetries sensitive to transitions beyond the Standard Model. A precise measurement of these $C\!P$ observables is crucial for a better determination of the quark-flavour mixing phases.In this article we report the results obtained by LHCb on the time-dependent and time-integrated $C\!P$ asymmetries using events of charmless b-hadron two-body decays collected during the Run1 data taking period and corresponding to $3~\mathrm{fb}^{-1}$.