The invention concerns benzamide compounds of Formula (I), wherein R1a, R1b, R1c, R2, R3, R4, m and n have any of the meanings defined in the description; processes for their preparation, pharmaceutical compositions containing them and their use in the manufacture of a medicament for use as an antiproliferative agent in the prevention or treatment of tumours or other proliferative conditions which are sensitive to the inhibition of histone deacetylase (HDAC).