By Justin Parkinson
Political reporter, BBC News

Members of a UK and Ireland transport union have voted overwhelmingly to merge with a US counterpart.

In a ballot, 85% of TSSA members backed joining the larger International Brotherhood of Boilermakers, which the leadership hopes will happen in July.

TSSA general secretary Manuel Cortes said a merger would bring “strength and security… at a time when our members need support”.

Officials are meeting later this month to discuss how it might work.

Currently, the TSSA – which represents workers including control centre staff, engineers, travel agents, train supervisors, ticket office and gate staff – has around 18,000 members, while the IBB has more than 50,000.

Some 4,322 (85%) of TSSA members who cast ballots were in favour of a merger, while 767 (15%) voted against. Turnout was 32%.

Mr Cortes said: “Our members and activists have spoken loud and clear that they back the proposed merger with the Boilermakers. The merger will bring strength and security to our TSSA union at a time when our members need support.

“Our union’s leadership will now be putting our collective shoulders to the wheel to act on the wishes of our members by making the proposed merger a reality.”

There has been a movement towards amalgamated unions over the past few decades, but international links have tended to remain relatively informal.

However, in 2009, the two Nautilus seafaring unions – based in the UK and Netherlands – combined to become Nautilus International.