Londoners are still facing severe delays on the central line this afternoon after a full day of disruptions to the central line tube service.
A derailment of an engineering train at Holland Park forced a part closure of the line at midnight last night, and the effects were still being felt by commuters this morning.
Mick Cash, general secretary of the RMT transport union, said:
Our officials are seeking to obtain further information on the serious derailment last night. While the union seeks to establish the facts, the incident once again throws under the spotlight the ever present issue of safety on the Underground for both staff and passengers alike.
The Rail Accident Investigation Branch is looking into the derailment.
Another incident this afternoon has caused further delays.
TFL has confirmed that a woman has died after she stepped in front of an underground train at Liverpool Street at around 1pm, leading to the second closure of part of the line.
This is the second consecutive day that the Underground has suffered disruptions, with three lines causing delays yesterday morning.
Although the line is now fully open, travellers have been warned to expect delays: