Closure date for BBC Radio 4 longwave on 198 kHz will be 26 September 2026 Arqiva (the tx operator) staff have been informed.
It's not yet known if the transmitters will remain on air for the Radio Teleswitch Service after this date, or if that will end at the same time. It could stay on air without R4 programming after this date (as Allouis 162 kHz has) because there are many (thousands) of electricity meters controlled by data transmitted on this frequency.