Royal Mail is to face potential strike action over planned changes to its pension scheme, after its largest union formally served notice of its plans to ballot its members.

The Communication Workers’ Union (CWU) today confirmed plans to call a ballot for industrial action over a number of changes to working conditions, including pensions, a shorter working week, and pay.

The ballot will open on Sept 14. The union represents around 100,000 Royal Mail workers.

The news comes just weeks after Royal Mail offered a fresh pensions deal to workers, allowing them to choose between a new defined benefit scheme or a defined contribution scheme, set up as a new section of the Royal Mail Pension Plan and available for all plan members.

Royal Mail had said it cannot maintain the existing final salary pension scheme as it faces having to more than double its contributions from next year.

But despite extensive talks, the CWU said that the company and the union have failed to reach a deal on plans to scrap the existing scheme next March.

As a result, it has served the Royal Mail with its plans to ballot members.

Terry Pullinger, CWU’s deputy general secretary for postal, said: "Talks have been taking place since April 2016, but the sense of shared purpose has drifted as privatisation has evolved.”