Talks expected to be held in an attempt to avert a strike by London Underground workers in a row over the new all-night Tube have failed to go ahead.
The operator said it was “extremely disappointed” that discussions were not held at Acas, the conciliation service.
Members of the drivers’ union Aslef and the RMT union are due to walk out for 24 hours from the evening of Wednesday 8 July.
The unions are in dispute over pay and conditions for the new all-night Tube, which is due to start at weekends from mid-September.
“Unfortunately, Aslef were unwilling to meet us at Acas. This is extremely disappointing, as we have made ourselves available to meet with them to continue negotiations,” said London Underground’s chief operating officer, Steve Griffiths.
“I encourage Aslef and all the trade union representatives to get back round the table, to help achieve a deal that is fair, affordable and sustainable.”
LU said it will return to Acas hoping that talks can be held.