Parcelforce worker Ellie Long announced the ballot result to loud cheers at Manchester's Mechanics’ Institute — birthplace of the Trades Union Congress in 1868.
More than 111,000 CWU members were balloted and returned a thumping 89 per cent in favour of strike action on a massive 73.7 per cent turnout - 72,872 of the 81,831 ballots returned voted Yes with just 8,954 voting No.
Ms Young said that it was “the best campaign” she had ever seen in the company combining traditional workplace meetings with a wide-reaching social media offensive.
It was the first national test of the Tory Trade Union Act under which ballots need a 50 per cent turnout to take lawful industrial action.
CWU general secretary Dave Ward said that the union had always turned out good ballot results but that the new legislation had spurred the union on.
He said the row provoked by Royal Mail's attack on workers' pensions was a “watershed dispute” and said unless Royal Mail bosses get back round the table it was “inevitable” that there would be strike action.
He told the People’s Assembly that the union had set out a “clear position at this year’s TUC” calling on people to “come together to end in-work poverty, to end austerity and fight for a new deal for workers.”
CWU deputy general secretary Terry Pullinger called on shambolic Royal Mail managers to resign or be sacked for the direction they are taking the company in.
“This result is a massive message to the company and it is a massive vote of no confidence,” he said.
Mr Pullinger explained that the workforce had seen through Royal Mail bosses who had “bombarded” members with material calling on them to vote no in the ballot.
He said the dispute had been going on for 18 months after former business secretary Vince Cable, now Lib Dem leader, had “sold-off Royal Mail cheaply for a promise which is being broken.”
“They have taken all the low-hanging fruit,” he said, accusing privateers of asset-stripping Royal Mail at the expense of workers’ terms and conditions and pensions “while at the same time worsening the service.”
Mr Pullinger said: “£1 billion has been stripped out of the company going into hedge funds” since Royal Mail was privatised.
“But we are still delivering to 30 million households, six days a week at a uniform price.
“The Royal Mail is one of this country’s greatest social developments but it has been sold-off to fill a few people’s pockets with gold,” he stormed.
Mr Ward added: “Postal workers are under relentless pressure to work faster, harder and cheaper.
“This has nothing to do with driving growth and innovation, it’s all about the tired old thinking of privatisation and asset-stripping.”
Under the Tories’ Trade Union Act, industrial action must take place within six months of the ballot. The union did not rule out strikes over Christmas but said the next steps would be decided by members and the CWU executive committee.