Royal Mail has won a High Court injunction preventing next week's 48-hour strike by postal workers.
Earlier in October, members of the Communication Workers Union (CWU) voted massively in favour of industrial action, with 83% of those who voted backing the idea in a dispute over pensions, pay and jobs.
The strike had been scheduled to begin at noon on October 19.
Royal Mail says the CWU is in breach of its contractual obligation not to call for strike action until the external mediation process, which began on October 5, is exhausted.
It claims that an injunction is appropriate to prevent the deliberate inconveniencing of hundreds of thousands of people across the UK, as well as commercial loss to the company.
The CWU maintains it has been attempting to find a solution to the dispute for 18 months.
Granting the order, Mr Justice Supperstone said he considered "the strike call to be unlawful and the defendant is obliged to withdraw its strike call until the external mediation process has been exhausted".
The CWU has accused Royal Mail of carrying out a "relentless" programme of cost-cutting to maximise short-term profits and shareholder returns.
The union said the company had closed its defined benefit, or final salary, pension scheme, offering new entrants an "inferior" scheme which the CWU claim will leave them in "pensioner poverty".
The industrial action would have been the first strike at Royal Mail since the postal group was privatised in 2015.
The Communication Workers Union has served formal legal notice to Royal Mail of its intention to ballot members for strike action.
The result will be announced on Wednesday October 16, and if members decide to strike, action could take place on October 23. Dave Ward, CWU deputy general secretary said the strike was in response to the government's "destabilising" privatisation schedule.
Postal workers have pledged to step up opposition to Royal Mail privatisation, warning that the sell-off would be a "disaster" for the industry.
The Communication Workers Union called on Labour to make it clear that the party will renationalise the postal group if it wins the next general election.
Delegates at the union's annual conference in Bournemouth expressed their "total opposition" to the Government's plans to privatise the Royal Mail and set out plans to "reinvigorate" their campaign.
General secretary Billy Hayes said the union was sending a strong message to firms "circling" the Royal Mail by making it clear that privatisation was not necessary.
The conference agreed an emergency motion to continue campaigning against privatisation and to press Labour to repeal the postal service act which paved the way to the sell-off.