Kentish Town station is to stay closed until next week after its escalators have broken.
The problem has happened a year after Transport for London (TfL) closed the downwards escalator for four months to repair it.
This time TfL has closed the station altogether.
In an email to customers earlier on Tuesday, Transport for London said: "Engineers are working as quickly as possible to fix the problem."
It has suggested passengers use the 134 or 214 buses, which also serve both Camden Town and Tufnell Park, on the Northern Line.
The closure will affect people looking to attend Camden Fringe events at the Lion and Unicorn Theatre in Gaisford Street.
A TfL spokesperson said: "We apologise to customers at Kentish Town for the disruption to their journeys this week. The station has been closed in order to repair the escalators, which have developed a fault. Our engineers are working around the clock to restore them to service as quickly as possible.
"In the meantime, the Thameslink station remains open, and our staff are on hand to direct our customers to Camden or Tufnell Park stations, which are both nearby and accessible by frequent local bus services."
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