Transport for London (TfL) has confirmed that the start of tunnelling for the Northern Line extension has been delayed by six months.
A Ferrovial, Agroman and Laing O’Rourke joint venture was selected by London Underground in 2014 for the design and build of the link from Kennington to Battersea.
Tunnelling was expected to start this summer but will now get underway in early 2017.
A TfL spokesperson said: “In a project of this scale and complexity, modifications sometimes need to be made to the works schedule. However, the Northern Line extension remains targeted for completion in 2020.”
Construction is complete of the two 650t, 100m-long tunnel boring machines that will each undertake two drives to build the 3.2km-long, 5.2m-diameter tunnels.