A manifold of an oil or gas well is described. The manifold is a manifold other than a christmas tree. The manifold comprises a branch which, in a first configuration forms part of a flowpath to and from a bore of the manifold; and a diverter assembly comprising a housing having an internal passage. A part of the diverter assembly is locatable in a bore in the branch, to provide an alternative flowpath to or from the bore of the manifold via the diverter assembly. A method of diverting fluids is also described.