Pat Hansberry, General Manager of the Northern line, said:
The Northern line had delays between Edgware and Camden Town this morning as a result of an earlier signal failure in the Clapham Common area. This has resulted in problems with restoring the scheduled service. Our line control and depot staff are working flat out to ensure a good service operates on the line, and I apologise to customers who have been delayed this morning.
Transport for London is reporting that there are minor delays on the Northern Line between Camden Town and High Barnet, but commuters have been complaining of long queues to get into a station or on a train.