Easter holidaymakers could face travel misery after Eurostar managers voted overwhelmingly to strike following a row over lone working.
St Pancras-based members of the Rail, Maritime and Transport union backed walkouts by 51 votes to three following a dispute over an RMT representative and train manager who objected to managing a train along a section of the Eurostar route alone.
The union has said that lone working was unsafe and the manager was within her rights to refuse.
Originally March 25 - Good Friday - was mooted as a potential strike date when the the union asked its members to vote, but now the RMT has said no date has been fixed as talks were still ongoing.
The union said positive progress had been made in the dispute since the ballot opened last month.
General secretary Mick Cash said: "Since the ballot opened, Eurostar have taken the issues that have been raised by the union seriously and intensive and positive discussions have been ongoing.
"The union's executive will be receiving a report from those talks when it considers the matter further."
Eurostar would not comment while negotiations were ongoing.
