text: The 24-hour Underground service was originally scheduled for September, but was delayed over a dispute about pay and conditions.
  Following the breakdown of talks on Wednesday, union leaders said the launch would not happen this year.
  But during a trip to Japan Mr Johnson said: "We are going to have a Night Tube eventually."
  He had previously said he was "relaxed" about when the service was introduced, as long as it happened before the end of autumn.
  Mr Johnson said during a business visit to Japan: "We'll do a Night Tube and obviously I hope very much that the offer on the table, which is a very good one, is now communicated properly to the workforce of London Underground and I think we should just get on with it.
  "We've done without it for 150 years and I'm sure we can rub along a little bit longe,r but we are going to have a Night Tube eventually."
  Unions took industrial action during the summer having called for increased pay and a limit on how many all-night shifts their members would be asked to do.
  As negotiations between the unions and London Underground came to a halt,  Finn Brennan from drivers' union Aslef, said discussions had broken up because LU management had "mishandled" the process.
target: London mayor Boris Johnson has backed away from a timetable for the opening of the city's Night Tube.