There is disclosed a mobile telephone handset having a casing including first and second components that slide relative to each other between a closed and an open configuration of the handset. The first and second components are interconnected by an electrically conductive connector, and facing surfaces of the first and second components are provided with electrically conductive surfaces or coatings that define an additional capacitive radio frequency path between the first and second components. The additional capacitive radio frequency path helps to divert radio frequency currents that might otherwise flow through the electrically conductive connector and thereby adversely affect performance of the handset.