There is provided inter alia a substrate with a surface having a hydrophilic coating comprising a cross-linked copolymer of components A and B, and optional components C and D wherein component A comprises one or more C2-C16 hydrophilic monomers each bearing one or more alkene and/or alkyne groups component B comprises one or more hydrophilic polymers each bearing two or more alkene and/or alkyne groups component C, if present, comprises one or more beneficial agents each bearing one or more alkene or alkyne groups and component D, if present, comprises one or more low molecular weight cross-linking agents each bearing two or more functional groups independently selected from thiol, alkene and alkyne groups wherein the cross-linked copolymer is formed by radical polymerisation involving the alkene and/or alkyne groups of components A, B and C (if present) and involving the functional groups of component D (if present) wherein the hydrophilic coating optionally comprises component E which comprises one or more beneficial agents, wherein component E does not form a copolymer with components A, B, C (if present) and D (if present) and wherein the hydrophilic coating is covalently attached to the surface of the substrate.
