Tube unions and London Underground bosses have again butted heads over rail safety on the Tube network.
Rail union TSSA announced on Thursday (February 18) that rail control staff will be balloting for strike action in a row over safety.
In a letter addressed to London Underground bosses, the TSSA threatened the strike ballot unless talks get underway with in the next few days.
In response to the strike ballot threat, the London Underground boss said the strike ballot was unnecessary, calling for talks to take place in an effort to resolve the dispute.
Chief Operating Officer Steve Griffiths said: "Safety is always our top priority and we have robust and comprehensive procedures in place to ensure the safety of our staff.
"TSSA’s threat to ballot for strike action is unnecessary, we urge them to continue to talk to us to resolve their concerns and avoid subjecting Londoners to another pointless strike threat.”
The TSSA Leader quickly responded to the comments, saying the company is guilty of "imposing change without negotation".
TSSA leader Manuel Cortes said: " Yesterday, I wrote to London Underground seeking urgent talks to resolve the issues affecting our members in Service Control.
"The company is guilty of breaking agreed procedures and imposing change without negotiation. If they are serious about resolving our concerns, they should reply to my letter to name when and where they are prepared to meet us.
"As I told them in my letter, we are available to engage in talks to resolve this dispute any time and anywhere."
The news comes as RMT union drivers working on the Piccadilly line said they will ballot for strike action next week in a similar row about safety on the underground network.
The Piccadilly is the fourth busiest line on the Tube network, linking Heathrow Airport to the rest of the capital.
A strike on the Piccadilly line would likely cause travel misery for London commuters.