An insecticidal compound of formula (I), wherein Y is a single bond, C═O, C═S or S(O)m where m is 0, 1 or 2 R1, R2, R3, R4, R8 A1, A2, A3, A4, B1, B2, B3 and B4 are specified organic groups or salts or N-oxides thereof compositions containing them and their using in controlling insects, acarines, nematodes or molluscs.