Lithographic printing plate precursor comprising: a) an untreated or pretreated substrate and b) a radiation-sensitive coating comprising: (i) at least one polymeric binder soluble or swellable in aqueous alkaline developers; (ii) at least one free-radical polymerizable monomer and/or oligomer comprising at least one non-aromatic C—C double bond and at least one SH group in the molecule; and (iii) a radiation-sensitive initiator or initiator system for free-radical polymerization, wherein component (ii) has the formula (I) wherein each R1a, R1b and R1c is independently selected from H, C1-C6 alkyl, C2-C8 alkenyl, aryl, halogen, CN and COOR1d, wherein R1d is H, C1-C18 alkyl, C2-C8 alkenyl, C2-C8 alkynyl or aryl; and Z is an aliphatic, heterocyclic or heteroaromatic spacer or a combination of two or more thereof, wherein Z can optionally comprise one or more additional SH groups and/or one or more additional non-aromatic C—C double bonds; and each Z1 is independently selected from a single bond, formulae (Ia), (Ib), (Ic), (Id), (Ie), (If), (Ig), (Ih), (Ij), (Ik), (Im), (In), (Io), (Ip), (Iq), (Ir), (Is), (It), (Iu), (Iv), wherein R2a, R2b and R2c are independently selected from H, C1-C6 alkyl and aryl, Z2 is selected from a single bond, O, S and NR2c, Z3 is a single bond which is connected to Z, b is an integer from 1 to 10 and c is an integer from 1 to 3.