The Government is threatening to change the law so agency workers can fill in striking staff, but the RMT says the move will be met with "fierce resistance" from the trade union movement.
A report in the Sunday Telegraph claims Transport Secretary Grant Shapps has not ruled out a rule change that would reverse a restriction that stops employers from hiring agency workers to cover for striking staff, and would apply it to all sectors, including transport.
The report comes ahead of three days of train strikes planned by Rail, Maritime and Transport (RMT) union members working for Network Rail and 13 leading train operators in the UK, including LNER, Northern, CrossCountry and TransPennine.