A positive-working lithographic printing plate precursor is disclosed which comprises on a support having a hydrophilic surface or which is provided with a hydrophilic layer a heat and/or light-sensitive coating including an infrared absorbing agent, said heat and/or light-sensitive coating comprising a first layer comprising a binder including a monomeric unit including a sulfonamide group; characterized in that the binder further comprises a monomeric unit including a phosphonic acid group or a salt thereof, and that the monomeric unit comprising the phosphonic acid group is present in an amount comprised between 2 mol % and 15 mol %.