Transport unions are using London's forthcoming Night Tube to recruit more members to their cause, IBTimes UK has discovered. London Underground (LU) has currently hired 436 extra station staff and part-time drivers to work on the 24-hour weekend service, which is expected to launch in August across the Victoria and Jubilee lines.

More than 180 part-time train operators will eventually work on the Night Tube, alongside drivers and station staff already employed on the Underground.

A source close to the Associated Society of Locomotive Engineers and Firemen (Aslef) told IBTimes UK the tube drivers' union has held a membership drive. "Out of the first 30 who started in training, [Aslef] signed up virtually all," the source claimed.

Other transport unions, such as the Rail, Maritime and Transport Workers Union (RMT), are thought to be making similar moves in a bid to bolster their numbers and strengthen their collective bargaining positions.

Transport for London (TfL) told IBTimes UK they are still filling the Night Tube roles with internal and external hires. Some former station staff have been effectively promoted into new part-time driver positions.

"Training is underway and each course takes 14 weeks to complete. We have a course starting most weeks at the moment and the first trainees are around four weeks through their programme," a TfL spokesperson said.

The Night Tube was originally planned to roll-out in September 2015, but an industrial dispute over pay and work conditions with the Underground unions delayed the launch.

RMT and Aslef members have since agreed a deal with LU over the new service. However, Unite wants to hold more talks with Underground bosses and the Transport Salaried Staffs' Association (TSSA) will stage a referendum on the issue on 21 March.

A TfL spokesperson added: "No date has yet been agreed for the launch of the Night Tube, but we are working hard to deliver it for London as quickly as possible."