A 24-hour service was originally scheduled to begin last month but has been delayed while lengthy talks over pay and working conditions continue. Another meeting was held Wednesday but failed to break the deadlock, The Daily Mail reported.
"We have put forward a number of proposals to resolve this dispute in a way that is fair and benefits both sides. London Underground have rejected them all," Finn Brennan of ASLEF was cited by the newspaper as saying.
"Underground management have completely mishandled these negotiations," Brennan said.
The 24 hour service was due to start on weekends September 12 on certain lines. The London Underground said it wanted to launch the new service because of a huge increase in passenger numbers, especially on weekends.
Unions took industrial action during the summer, with officials pressing for a pay rise and a limit on night shifts for each employee per month.
