In oups.com,
Simon Lane typed:

asdf wrote:
BBC News 24 reporting a "code amber" - shutdown of entire
Underground

Now changed their story - only Vic, Northern, H&C have been shut

Interestingly R5 are describing this as a "code amber on three lines".

That's what 'code amber' means. All trains draw forward to platforms,
passengers are evacuated to ground level and services suspended.

--
Bob