Rail workers at Greater Anglia are to go on strike - in a row over the role of guards and driver-only trains.
The RMT Union says members voted overwhelmingly in favour of industrial action after Abellio - which runs the franchise - failed to give assurances on their future.
They claim the potential extension of the Driver Only Operation is "a clear threat to passenger safety".
Over 200 Greater Anglia guards voted nine to one for strike action, while the drivers vote was two to one for action.
RMT General Secretary Mick Cash said: "Greater Anglia have been given every opportunity to give a guarantee on the future role of the guard on their services.
"They have failed to do so and that left us with no alternative but to move to a ballot in the interests of rail safety.
"Our members have now voted by massive majorities for action and it's now down to the company to wake up and take note and to seize the opportunity to give us the very simple assurances on the future of the guards, and the guarantee of a second safety critical member of staff on current services.
"The union remains available for further talks around the crucial issue of the guard guarantee."
The result will now be considered by RMT's executive who will decide on the next steps in the dispute.
Greater Anglia insists it's got no plans to axe guards on services.