The vast majority (97.1%) of around 110,000 voters backed a strike from a 76% turnout of CWU members, representing both one of the largest ‘Yes’ votes and turnouts for many years.

Hundreds of CWU reps waved union flags and cheered as the result was announced after a national reps’ briefing in London yesterday (15 October).

For legal reasons, CWU’s Parcelforce members were balloted separately in two separate ballots, one on the controversial TUPE proposals – Royal Mail wants to split Parcelforce off into a separate company with the workforce TUPE'd across, and the other on the rest of the issues in dispute, including job security and terms and conditions of employment. Both of these also returned large ‘Yes’ votes – of 94.7% and 95% respectively.

Strikes at Royal Mail were averted last year after the postal service agreed to increase pay, reform pensions and reduce weekly working hours from 39 to 35 by 2022, subject to productivity improvements.

CWU said the agreement is not being honoured by the company’s new leadership but Royal Mail has said it is abiding by the agreement and has awarded two pay rises since last year.

CWU general secretary Dave Ward called the result “historic”.

“The workforce has completely rejected the company’s plans to set up a separate parcels business and allow UK postal services and thousands upon thousands of jobs to wither on the vine,” he said, also highlighting other issues of grievance such as increased workload pressure on members, driven by technology.

“This dispute goes to the heart of everything that is wrong in today’s world of work,” he added, vowing to “fight the board’s asset-stripping plans, not just through strike action, but by speaking directly to major shareholders, politicians and the public”.

“We will build a coalition for change and deliver an exciting and innovative future for Royal Mail, with an expanded role for postal workers in supporting local communities and growing the economy.”

While strike dates have not yet been announced, there has been speculation that the union could target Black Friday in late November and the Christmas post.

In a statement, Royal Mail said it was “very disappointed” in the result.

“A ballot result for industrial action does not necessarily mean there will be industrial action. We are still in mediation with the CWU. Under our Dispute Resolution Procedure, set out in the Agenda for Growth, we are committed to reaching a resolution.

“No industrial action can be taken, and formal notification of industrial action cannot be given, before the conclusion of the Dispute Resolution Procedure.

“We want to reach agreement. There are no grounds for industrial action. Industrial action – or the threat of it – is damaging for our business and undermines the trust of our customers.”

The length of the mediation is unclear, and a Royal Mail spokesperson told Printweek “it is our policy not to comment on the mediation process”.

Royal Mail has sent its customers suggested replies to questions from their own clients. The email correspondence, which has been seen by Printweek, offers responses including: “It’s business as usual at Royal Mail”, “they remain focused on our normal high-quality levels of service” and “they continue to accept, process and deliver mail for our customers”.

Central Mailing Services managing director Mitesh Chouhan told Printweek: “Royal Mail strikes are never good for business but let’s hope a compromise is reached and it is business as usual. December is never a great time for post due to peak, Christmas, [and] weather so a strike will just cause more delays.”

CWU’s high-profile social media campaign garnered a wide spread of support, including from Labour leader Jeremy Corbyn, who tweeted: “Thousands of posties have voted yes in record numbers for strike action in defence of their jobs. Royal Mail is a Tory-Lib Dem privatisation failure. Its sell off led to shareholders creaming profits off the top while running down the service.”

Royal Mail's share price was up by 1.7% following the results of the ballot yesterday to 216.4p but had since dropped back to 210.74p at the time of writing.