It is understood the government has changed its guidance to rail operators around the opening hours of ticket offices.
According to the RMT, this change could lead to the closure or reduction in opening hours at railway station ticket offices across the network, slashing thousands of jobs and creating a ‘muggers paradise’.
RMT general secretary Mick Lynch said: “The rail industry has made no secret of its goal of closing all ticket offices, and the floodgates have now been opened for an annihilation of ticket offices across the network.
“Ticket office staff not only enhance the passenger experience, but they ensure our railways are safe, secure and accessible. Wholescale ticket office closures would be disastrous for passengers and leave our railway deserted. Disabled and elderly passengers will be particularly affected.
“This once more proves that the government’s 'levelling up' agenda is a sham and that England's rail is being downgraded driving unnecessary social tensions between Britain's nations and demonstrating a political choice has been made to downgrade England's rail users compared to Wales and Scotland.
“Make no mistake, RMT is ready to use all means at our disposal to fight any attacks on ticket offices, we will be launching a widespread public and political campaign to protect ticket offices and our station staff members’ jobs.”
Analysis by the RMT suggests that more than 1000 ticketing offices across 15 different operators are at risk.
The operators named by RMT include Northern, Great Northern and Thameslink, Great Western Railway and Southeastern.
A Department for Transport spokesperson said: “The Government has committed £16bn of funding for passenger services since the start of the pandemic. Equivalent to nearly £600 per household. We need to take the rail industry off taxpayer life support.
“The reality is that ticket offices have seen a significant decline in use since the 90s yet numbers have not substantially changed since then.
“Staff will always provide face-to-face services on the railways, which can be crucial for those who need additional support and cannot, or do not want to, use contactless or mobile tickets.”
A spokesperson for the Rail Delivery Group, which represents train operators, said: “The pandemic has been an unprecedented financial shock to the railway. While no decisions have been taken over ticket offices, with the acceleration of changing travel patterns and more passengers migrating to digital technology, many jobs will need to change to become more passenger-centric.
"Train companies want to work with unions on how to address those changes, while making sure the industry takes no more than its fair share from the taxpayer.”