Cllr Claudia Webbe, executive member for environment and transport, said: “Islington residents and commuters across north London have been extremely patient while Network Rail upgrades this important line. Many have suffered huge upheavals and had their daily routines disrupted as a result.
“I welcome the reopening of the line, and the replacement of outdated and polluting diesel engines with electric trains along this route in 2018.
“But I am angered and disappointed that Network Rail has fallen so far behind schedule. Further closures on the line now look unavoidable, and work is still required on the bridge at Crouch Hill.
“This will extend disruption for commuters and residents well into the summer months. It is not fair for them to suffer even more from a catalogue of errors and mismanagement of works.
“The council and TfL pulled out all the stops to make sure the bridge work on Holloway Road this winter would not delay Network Rail’s upgrade project.
“Yet Network Rail has failed to capitalise on the sacrifices made by our residents and tens of thousands of road users.”