The UK faces its first major strike in the steel industry for more than three decades after thousands of Tata Steel workers voted overwhelmingly in favour of industrial action.

Unions representing Tata’s 17,000 workers have spent months locked in a dispute with the UK’s biggest steelmaker about proposed changes to their final salary pension scheme.

Community — Tata Steel’s biggest union representing more than 6,000 of the company’s UK workforce — said on Friday 88 per cent of 4,600 members who took part in a ballot voted to strike.

“This is a clear demonstration of the anger and concern and loss of trust in Tata Steel’s values,” said Roy Rickhuss, general secretary of Community. The average turnout was over 76 per cent, the union said, and as high as 84 per cent at the company’s Port Talbot steelworks, where 96 per cent voted for strike action.

Results of ballots by GMB and Ucatt members were also expected on Friday. Unite, another union, was in the process of balloting its 6,000 members, with the results expected next Friday.

The Community ballot result comes two months after Tata Steel announced plans to close a final salary pension scheme and move staff to a defined contribution scheme. The change would affect about 16,000 workers and mean they would have to retire at 65 instead of 60.

The pension deficit is thought to be in the region of £2bn. Tata Steel estimates the closure will create savings of about £1bn.

In a letter to employees on Friday, Karl Koehler, chief executive of Tata Steel’s European business, wrote: “I understand and recognise colleagues’ frustrations at this situation. But I would ask them not to support industrial action to retain unaffordable early retirement benefits. Ultimately, such action would be self-defeating and would jeopardise our efforts to build a sustainable business in the UK.”

Alan Coombs, who works at Tata’s Port Talbot plant and chairs the multi-unions committee, said the result showed how concerned workers were.

“It’s a big decision for our union as we’ve tried to work in partnership with the company for the last 35 years. It is disappointing and it is heart-wrenching in some respects but we feel like we have no alternative at the moment,” he said.

Mr Rickhuss urged Tata to engage in full negotiations to avert a strike. “We hope they take serious notice of this result. This is members saying enough is enough.”

Community said its national executive council will meet on Monday to discuss the next steps.

Responding to the ballot result, Tata said: “The result of the pension ballots announced earlier today is disappointing, given the company is proposing to continue providing employees with highly attractive and competitive pensions.

“The company has already stated to both the trade unions and employees, in response to the feedback received through the consultation process, that it intends to mitigate the impact of the proposed changes.”

The threatened strike caps a tumultuous time for the UK’s struggling steel industry, which has been hit hard by falling demand and a lack of investment.

While global production has doubled in the past four decades, the amount the UK produces has halved. It now makes just 12m of the 1.5bn tonnes of steel produced globally. The number of people employed has also shrunk, falling from 200,000 in the early 1970s to about 18,000 today.

The UK steel industry is battling against cheap imports from countries such as China, weak demand and high energy costs, driven up by green taxes that are higher than in other nations.

Since buying Anglo-Dutch steelmaker Corus for $13.1bn in 2007, Tata’s European business has been forced to slash costs and cut jobs as it struggled amid falling demand. The group this month announced a writedown of its European assets of more than £500m — the second writedown in two years after a £1bn charge in 2013.

Most of the job cuts have been across Tata’s lossmaking UK operations. The number of people it employs in the UK has fallen from 25,000 in 2008 to 17,000 today.

It is also in the midst of talks to sell its European long products division — which employs 5,900 in the UK and another 600 across Europe — to Geneva-based industrial group Klesch.

The sale would include some of Tata Steel’s biggest UK assets, including its Scunthorpe steelmaking plant, which employs 4,000. The division, which makes steel that is used for building and to make rails for train lines, accounts for about a third of the company’s UK workforce.