UNION officials have not ruled out further strike action by Tube workers.

Services on the London Underground returned to normal last night after a 48-hour walkout came to an end.

The Rail, Maritime and Transport Union (RMT) is calling for a 5 per cent pay rise and insists it has a mandate for further industrial action.

Further talks between the union and Tube bosses are planned next week.

RMT leader Bob Crow said: "We are still pushing for the direct, top-level talks that are needed to end this dispute."

Transport for London said letters had been exchanged through concilitation service Acas to set out the basis for future discussions.

The Victoria and Central lines were among nine lines affected by the strike, leaving commuters in Waltham Forest, Redbridge and Epping Forest struggling to get to work.