1. A navigation apparatus comprising: a processing resource arranged to support an operating environment; a route follower supported by the operating environment and arranged to monitor progression, when in use, along a route to be followed; an instruction generator supported by the operating environment and arranged to determine an identity of a location in advance of the location being reached where a manoeuvre has to be executed in order to continue following the route, and to generate manoeuvre data in relation to the manoeuvre; and a voice command generator supported by the operating environment and arranged to obtain the manoeuvre data and to generate in response to the manoeuvre data voice instruction data for reproduction by a loudspeaker as an audible voice instruction; wherein the manoeuvre data comprises route manoeuvre instruction component data and supplementary descriptive instruction component data.