Severe disruption on the Victoria Line has led to station access being restricted due to overcrowding fears.
There are severe delays at Seven Sisters station, with 25-minute queues reported.
Passengers took to Twitter to complain about the situation at the north London station.
Seven Sisters station is zombie apocalypse bad this morning, paramedics, yelling, everyone panicking. End of days!— Nikki Plummer (@plumtingz) December 13, 2016
There are similar crowds outside Finsbury Park and Highbury & Islington stations.
My morning in pictures left station is Finsbury Park right Highbury and Islington pic.twitter.com/YyTkzEOmA2— Mitch Rhodes (@mitchrhodes) December 13, 2016
A number of Piccadilly Line trains are not stopping at Finsbury Park, with passengers advised to use alternative routes.
Meanwhile, Transport for London warned that Brixton station is "very congested" and advised commuters to travel by different routes.
Brixton station is very congested due to a signal failure and Southern Railway strike https://t.co/eSxsJq44tT Pls use use alternative routes— Victoria line (@victorialine) December 13, 2016