A lithographic printing plate precursor is provided which comprises an aluminum support having a hydrophilic surface and a coating provided thereon, said coating comprising a photopolymerisable composition having a polymerisable compound, a pigment dispersed with a dispersant, a polymerization initiator and a binder, characterized in that the dispersant is a compound free of -COOH, - PO 3 H 2 or -OPO 3 H 2 groups, and the polymerization initiator is a trihalomethyl-aryl sulphone wherein the aryl group is substituted by at least one electron-donating group and wherein the sum of the Hammett constants (sigma) of the substituting groups on said aryl group has a negative value.
The printing plate precursor exhibits an excellent daylight stability and shelf-life.