A London tube train hurtled along at speeds of up to 40mph on Saturday morning with its doors wide open.
Christiano Nops filmed as the Jubilee Line train travelled between Finchley Road and West Hampstead stations on Saturday morning.
He later uploaded the clip, which shows a number of travellers seated in the carriage, on Instagram.
His friend Rory Brown shared the clip on Twitter, adding another message to Transport for London.
‘Pretty bloody sketchy! #whatishealthandsafety?’
In response to a Twitter user who expressed shock that no one had pulled the emergency handle on the train, Mr Brown clarified that at least 10 doors on one side of the train were open.
TfL responded to the clip on Sunday, saying they were aware of the incident and that the faulty train had been taken out of service.
‘Hi Rory, we were made aware of this yesterday and the train was taken out of service and currently under investigation so thanks for letting us know,’ TfL tweeted in reply to Mr Brown’s post.
‘Sorry for any inconvenience caused and hope your journey was okay.’
MailOnline has contacted TfL for further comment.