Poly(benzyl methacrylate)-magnesium phyllosilicate nanocomposites were synthesized using a novel in situ intercalative ambient temperature atom transfer radical polymerization (ATATRP). The organic moiety in the synthesized magnesium phyllosilicate was modified to initiate ATRP, in the presence of Cu(I)/PMDETA. Exfoliation was achieved and this process was rapid. The anchoring efficiency of the polymer chains on the organically modified phyllosilicate increased with silicate loading. This route to nanocomposite preparation is expected to be general and viable, and superior in comparison to the melt mixing route which did not result in the formation of a nanocomposite in these systems. © 2010 Elsevier B.V.