Current Web Modelling Languages (WMLs) fall short of the requirements for the modelling of web system development. In particular, those WMLs with a hypermedia basis are more closely focussed on the information architecture whereas software WMLs are more focussed on the functional architecture. Generally, modelling languages have failed to bridge the gap between these two areas, nor do they handle well the connection between different levels of abstraction and are largely unable to connect well with business models. Based on an analysis of existing modelling approaches, we propose a conceptual extension to modelling approaches that attempts to address these limitations. We show how it can implemented using UML modelling along with the addition of concepts taken from Web information modelling approaches, WebML in particular. The extensions are structured around the model-view-controller concept, which we argue provides an appropriate integrating modelling framework. We begin by discussing the scope and objectives of the extensions, followed by the extensions themselves. We then illustrate the extensions using a small case study.