The polymerisation of N-acryloylmorpholine in water is reported utilising Cu(0)-mediated living radical polymerisation (SET-LRP). The inherent instability of [Cu-I(Me-6-Tren)Br] in aqueous solution is exploited via rapid disproportionation to prepare Cu(0) particles and [Cu-II(Me-6-Tren)Br-2] in situ prior to addition of monomer and initiator. Quantitative conversion is attained within 30 min for various degrees of polymerisation (DPn = 20-640) with SEC showing symmetrical narrow molecular weight distributions (D < 1.18) in all cases. Optimised conditions are subsequently applied for the preparation of a diblock copolymer poly(NIPAm)-b-(N-acryloylmorpholine), illustrating the versatility of this approach.