The overall aim of this work, sponsored by BASF, was to investigate the effect of the solvent, ligand and initiator, upon the Cu(0)-mediated reversible deactivation radical polymerisation (RDRP) of water-soluble monomers. In addition to this, the simplicity and versatility of the aqueous methodology led to a secondary goal; the determination of reaction conditions that would allow for polymerisations to be conducted in an “off the shelf” manner. As a starting point for this study, two bidendate and five multidentate ligands were screened as mediators for the controlled polymerisation of N-isopropylacrylamide (NIPAm) (Chapter 3). From these results, the polymerisations which involved tris[2-(dimethylamino)ethyl]amine (Me6TREN) were deemed to be the most successful. However, as Me6TREN was expensive and thus required synthesising, further investigation was carried out. Following characterisation by UV-Vis spectroscopy and the optimisation of reaction conditions, it was suggested that N,N,N’,N’’,N’’-pentamethyldiethylenetriamine (PMDETA)) and (tris(2-aminoethyl)amine (TREN) were more suited to “off the shelf” polymerisations. To continue the development of such a system, four initiators were employed for the synthesis of PNIPAm (Chapter 4). During this investigation, 2-bromo-N-(2-hydroxyethyl)-2-methylpropanamide (compound (3)) was identified as being the most appropriate initiator for a “synthesis-free” polymerisation. In Chapter 2, a system for the well-controlled polymerisation and in-situ depolymerisation of acrylamides and acrylates was developed. In addition to this and following the reformation of monomer, deoxygenation of the resulting solution furnished high conversions and low dispersity polymers within 30 minutes.