A continuity announcer is a certain announcer who is seen or heard in TV during continuity, i.e. between shows, to bridge the gap and give the viewer some information about what is to come next. The continuity announcer reads up on the programmes and present them to the viewers in a factual tone, sometimes also telling what is coming the next day or on other channels, if the other channels belong to the same broadcasting company.
There is a certain tradition about continuity announcers in the United Kingdom.
References
Continuity announcer Wikipedia(Text) CC BY-SA