On 16 May, 09:51, Mike Bristow wrote:

http://www.flickr.com/photos/25124954@N00/480556440/

Come down the Northern escalator at Warren Street, and right in front of
you are two foot tunnels, one on the left and one on the right. This is
the wall between them.

There may well be a machine room under the floor with all the escalator
machinery. This may be the emergency exit from it. In other words,
keep clear because you're standing on a trap door! (The handles are
there to help someone clamber out).

However, the above is just a guess. Does the floor sound a bit hollow
thereabouts?

There is indeed a trapdoor, roughly below the 'keep clear' sign. It's
some distance from the foot of the escalators but might be a way into
the access space, or maybe it's just plumbing of some sort. I've not
seen it in use in 20 years of using the station, but the pictured
handrails have not been there that long.

The escalator motors are at the top landing, I seem to recall from
when they were last maintained.

Peter CS