London Underground bosses have repeated assurances that all stations will remain staffed under changes expected to be unveiled on Thursday.
The RMT union says it has been notified that “a major announcement” on jobs and services will be made to senior union representatives at 9am tomorrow.
The proposals are expected to include closing ticket offices and moving staff onto platforms whether they will be available to assist passengers and sell tickets via portable devices.
The union claims the announcement will also include “reductions in maintenance” and thousands of jobs losses.
LU has previously said the closures, first proposed in 2007, are necessary because the continuing success of Oyster means ever smaller numbers of passengers pay for their journey at ticket offices.
In October Tube boss Mike Brown told the London Assembly he would never agree to any proposal to move to unstaffed or part-time staffed stations and promised passengers would still enjoy a safe, reliable service.
RMT General Secretary Bob Crow claims the expected changes will lead “to a dangerous and hollowed out” network where “safety is compromised and passengers are left at risk the minute they step onto a station or a train.”
The union blames the changes on a £225m cut in central Government funding for Transport for London.
Mr Crow says his members “will fight these plans with every tool at our disposal and that includes political, public and industrial campaigning on an unprecedented scale.”
He added: “RMT will move quickly to make the necessary preparations for action that will confront these proposals head on and if the LU management under Boris Johnson don’t wake up and see sense that means, inevitably, industrial action across the entire network.”
Responding to the unions claims, Mr Brown said: “We will shortly set out our vision for a Tube service fit for the future and London in the 21st century.
“This will include a commitment that all Tube stations will remain staffed and managed while services are running, with more staff visible and available to help our customers buy the right ticket, plan their journeys and remain safe and secure.”