Cylinder lock

A barrel for a cylinder lock, said barrel comprising a generally cylindrical barrel body having end faces, a keyway formed in said barrel body and extending longitudinally inwardly from one end face, a plurality of guide bores formed in the barrel body and extending outwardly from said keyway so as to communicate therewith, a single lock pin slidably received within each said bores and retained therein so as to be movable longitudinally thereof from a position projecting into said keyway to a retracted position, with each pin being prevented from rotation about the longitudinal axis of the bore, said bores being grouped in two sets with the bores of each set being aligned longitudinally so that the two sets are ranged in a space generally parallel co-extensive relationship, two side bar slots formed in opposite sides of the body so as to extend longitudinally thereof, said body further having a passage extending from each bore so that the passages are arranged in two sets with each set of passages terminating at a particular side bar slot, the recesses of each pin being selectively alignable with the passage extending from the bore of the respective pin, and wherein said barrel further includes a side bar slidably located in each slot so as to be movable from a radially outer locking position to a radially inner release position, and each said side bar has a plurality of projections which are located in said passages and extend therethrough so as to be selectively locatable within the recesses of the pins to enable movement of the side bars to said release position.