See...Martin obviously is a person of knowledge.....

Its a regulation that you cant operate an 'underground' underground station
without an up escalator working. Something to do with people having heart
attacks and emergency escape etc.
However i think they may still be contravening this as if there was an
emegency the only way out is walking up....or by train. And most of the
people at Brixton always seem to gravitate to the train thats not going
next. So at least a few minutes before all people are evacuated.

Me