A lockable modular storage and support assembly uses a platform system that includes vertically disposed support posts (10). The support post has an extended tubular body and a plurality of symmetrically spaced, radially extending flanges (20) running the length of the tubular body. Each flange has a first portion extending radially from the post and a second portion (24) at the terminal end of the first portion. A slot (26) is defined between each pair of adjacent flanges for receiving vertical panels or other inserts. A security system with both manual and electronic controls is provided to lock the modular storage and support assembly.