Police are appealing for witnesses to the incident to come forward.
Although the woman has not yet been formally identified, her next of kin have been informed.
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Paramedics were on standby outside the police cordon as armed officers stood by the property.
A team of researchers has taken samples from the ten busiest London Underground lines to work out which are the dirtiest.
The action comes on top of an emergency timetable which has seen hundreds of trains a day being axed.