Two transport unions, the RMT and TSSA have agreed to hold talks on a merger.
They will focus initially on closer working through a federal structure with a view to moving towards a merger.
The RMT was formed in 1990 from the merger of the National Union of Railwaymen and the National Union of Seamen. It has about 80,000 members covering the main line and underground railways, shipping and offshore, buses and road freight.
The Transport Salaried Staffs’ Association was founded in 1897 and now represents 30,000 administrative, managerial, professional and technical workers in the railway, London Underground, the travel trade, ports and ferries.
RMT general secretary Bob Crow said: “This is a historical day for the trade union movement. These talks will bring together two unions each with over a hundred years of specialising in the transport industry in the interests of workers.”
The unions have left the doors open for other smaller specialist unions in transport to join the discussions at a future date.