BBC Radio 4 May Go Dark Soon?

From the ARRL Contest Update from 12 Oct 2011:

Long may it wave...but not much longer. The transmissions of BBC's station Radio 4 on 198 kHz emanate from a pair of meter-high "valves" that are irreplaceable. Once the remaining store of the big bottles is gone, the broadcasts may well go dark. On the air since 1926 and serving areas out of range of FM stations, transmission moved to 200 kHz in 1934 and then to 198 kHz where it can be found today. (Thanks, Tomas NW7US)

Post nuclear broadcasting from BBC Radio 4

For much of the last half of the twentieth century Britain, along with many parts of the world, faced possible annihilation by nuclear weapons.

While the population at large were being advised to hide under the tables and cover their windows with sheets, the BBC was preparing for post-Armageddon.

A string of secret bunkers across the country, many of them used during war time days, were converted into subterranean studios.

Play lists were drawn up, presenters given scripted announcements and producers issued with sets of keys.

If anyone was still alive to listen ‘Auntie’ would be there to entertain and inform them.

Mike Thomson goes in search of the hidden bunkers, the people told to staff them and a secret safe said to contain the unreleased running orders for what was to be called ‘Radio 10’.
Listen to the latest edition at:
http://www.bbc.co.uk/radio4/history/document/document_20080204.shtml