A spokesperson for Northern (Arriva Rail North) said: “Northern began the new franchise in April 2016 and is committed to an ambitious programme to modernise rail travel for our customers. The improvements will maintain high safety standards, deliver better journeys and improve customer service across the network.

Our plans for customers include new and refurbished trains, station improvements, more seats and extra services during peak periods. It is really important to us that our colleagues and their representatives are involved in discussing how to bring these improvements to life.

That means we are committed to sharing proposals when they are ready. This is not the time to talk about a potential dispute, we want to sit down and work positively with the trade unions.”