NORTHERN rail says a simple mistake was behind the displaying of posters at one of its stations which wrongly claimed a strike by RMT members had been cancelled.

The error was seized upon by the union which accused the company of an “outrageous campaign of dirty tricks”.

RMT members are due to strike for 24 hours on March 13 in a row over the role of guards – also known as conductors – on Northern trains.

The RMT claims the company has refused to give a guarantee that guards, whose job includes opening and closing train doors and collecting fares, will be retained under modernisation plans.

A number of rail operators elsewhere in the country have already moved to so-called driver-only operation, leading to disputes with the RMT which says guards have a critical safety role.

Referring to the poster, which was quickly removed, the RMT’s general secretary Mick Cash said: "Instead of pulling pathetic stunts like this the company should be round the table with the union negotiating a solution that gives the public the guard guarantee they want and which allows us to move on knowing that safety comes before profits."

A spokesman for Northern said: “The poster is part of a customer communications pack sent to our stations.

“These always cover every eventuality, especially in the event of strike action, as this allows us to get information out as quickly as possible to customers.

“Unfortunately one of our stations displayed the wrong poster which was quickly removed.”

The spokesman added: “We remain committed to constructive resolution and urge the RMT to continue the talks we have already started.

“We stress that we have had no communication from RMT that the strike on March 13 is cancelled.”