The decision means the UK’s largest remaining vertically integrated operator will not engage in a collective bargaining relationship with the trade union.

The snub comes following the collapse of Thomas Cook and led to TSSA general secretary Manuel Cortes writing to Tui managing director Andrew Flintham to point out that TSSA historically represented Thomson Travel staff.

However, Tui said it prefers "informal and formal networks" for staff to share their views and workplace concerns. 

Mr Cortes described these as "sham structures".

He said: “I would urge Tui to think again – they have nothing to fear from union recognition, which gives their staff a real say over their rights, pay and working conditions. 

“We already have several dozen members at Tui, and a truly progressive employer would not offer up sham structures as anything comparable with membership of our union."

Tui has been contacted for comment.