The BBC is reporting that CS gas was released in the ticket hall of Ealing Broadway Tube yesterday evening.
At around 6.45pm yesterday the gas was released (police are assuming by one of the commuters) and the station was closed, although main line trains continued running.
Six "fire appliances" (don't they call them 'engines' anymore?) were despatched to the scene and witnesses report seeing passengers emerging "coughing and spluttering" from the station.
If you were there at Ealing Broadway last night and you saw what happened, let us know in the Comments section.