http://websdr.ewi.utwente.nl:8901

One can listen to the live closure broadcast via this WebSDR website, by tuning it to AM 198 kHz.

"You are listening to 198 kHz longwave. BBC Radio 4 is no longer available on this frequency. However, you can find Radio 4 many other ways. You can find BBC Radio 4 online, via BBC Sounds. Radio 4 is available on DAB digital radio and through your digital television, including freely. Radio 4 is also available via FM radio, on 92 to 95 MHz and 103 to 105 MHz. Plus, you can listen via your smart speaker: just say 'play Radio 4'. Information on how to listen can be found on the BBC website, at bbc.co.uk/reception."