Jenny Reeves (@Jennyflyer1) was one of the first to post a picture on Twitter.
And Transport for London sounded the all-clear after the "invasion" had been averted.
The filming of Doctor Who has finished at Westminster Bridge, the Daleks are in the process of being removed.
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More than a tenth of the Piccadilly Line train fleet is out of action because of emergency repairs to damaged wheels.
Rows of students stood and turned their backs before filing out of the lecture theatre.
Effie the endangered Western lowland gorilla has given birth to a healthy baby boy at London Zoo.