Gospel Oak and Tufnell Park are set to be hit by traffic chaos from next week as transport chiefs have announced that Holloway Road will be closed for three months.

Islington Council is threatening to sue Transport for London (TfL) over the “last-minute” announcement, claiming it was left in the dark about the Upper Holloway bridge work. The Upper Holloway bridge is being replaced so the Gospel Oak to Barking London Overground line can be electrified – a project that has already closed Gospel Oak station until February.

Transport for London (TfL) was slammed for its “astonishing incompetence” by the leader of Islington Council, councillor Richard Watts, who said his staff had not been consulted about the closure.

Cllr Claudia Webbe, Islington’s own transport boss, said she was dismayed by the “short-notice and unplanned” closure.

The Upper Holloway bridge is being replaced so the Gospel Oak to Barking London Overground line can be electrified – a project that has already closed the station until February. Work began in 2014 and has already caused problems, but the latest disruption will leave drivers, cyclists and bus users all diverted along Tufnell Park Road and Junction Road.

TfL says work to transfer underground pipes and cables from the old bridge to another specially-made bridge has proved problematic because of their “complex layout, poor condition and a leaking water main”.

But Cllr Webbe was having none of it. She said: “It seems TfL underestimated the work needed, and claim there is no other choice but this last-minute arrangement, which will affect the lives of countless residents and businesses in Islington and far beyond. I have asked the council to consider our options, including legal, while challenging TfL to minimise the extent and scale of the disruption.”

Nick Fairholme, TfL’s director of surface works, said bosses were doing all they could to minimise the disruption and apologised for any delays.

The road will be closed to southbound traffic from October 21 until January 16 and northbound between October 21 and October 31; over the weekends of November 18 to 21; November 25 to 28; and from Christmas Eve until January 16. A journey planner has been created at tfl.gov.uk/upper-holloway-bridge.