ARTICLE AD BOX
By Felicity Evans
Money editor, Wales
Unions have claimed Tata Steel will close the bulk of its operation at the UK's biggest steelworks.
Tata's announcement about the future of its Port Talbot plant was anticipated on Wednesday but it is now not clear when its statement will be made.
Unions have responded ferociously to the proposals after they were briefed by Tata officials.
The GMB union said the plans would have "fired the starting gun on the death of UK steel" if they go ahead.
GMB, along with Community and Unite, promised to oppose the plans with every means at their disposal.
The UK government previously announced £500m to keep the Port Talbot site, which employs 4,000 people, open.
Tata Steel employs 8,000 people across the UK.
However, the money will see new electric arc furnaces replace existing blast furnaces, reducing the number of workers needed.
The company, which asked the government to provide further funds, is also investing £700m in the site.
Port Talbot's steelworks is one of the biggest polluters in the UK, with its two existing blast furnaces working around the clock.
The new £1.25bn greener arc furnaces are expected to be operational within three years of getting regulatory and planning approval.
The UK government said the deal "has the potential to safeguard" more than 5,000 jobs across the UK.
But the unions have criticised this plan, with GMB's national officer for steel, Charlotte Brumpton-Childs, saying: "Tata must pull back from the brink, work with us to deliver a better outcome for their workforce and protect UK virgin steelmaking.
"If this plan remains unchanged, Tata and UK government have fired the starting gun on the death of UK steel."
She warned closing down facilities while supplying mills with foreign steel would "put us on a collision course with massive industrial unrest".
Roy Rickhuss, general secretary of the Community union, said: "This disgraceful announcement from Tata Steel is another kick in the teeth for their loyal workforce and the Port Talbot community.
"The unions do not accept the closure of the heavy end and we continue to believe the blast furnaces are crucial to the transition to green steelmaking."
He added the unions would "never accept" the plan and would "oppose it with everything we've got".
Ahead of the expected announcement, Tata Steel said: "We hope to start formal consultation with our employee representatives, shortly.
"We believe our £1.25bn proposal to transition to green steel making will secure the business for the longer term, bolster UK steel security and help develop a green ecosystem in the region.
"We are committed to meaningful information and consultation process with our trade union partners about these proposals and will carefully consider any proposals put forward."