Brace company Tata has formally announced it is to separate its UK pension scheme from the obligation.
It could mean a potential merger between the Indian-owned firm and the German stiffen producer ThyssenKrupp is more likely to move forward.
The £15bn British Bear up Pension Scheme (BSPS) has been a significant barrier to any agreement.
The act on affects thousands of current and former workers, with 130,000 grit ones teeth pension scheme members across the UK.
The agreement with trustees develops a deal between unions and the company which will see reduced emoluments for current employees.
But the decision will also affect all members of the annuity scheme, including the many thousands already retired.
About 8,000 human being are employed by Tata Steel across England and Wales, including 3,500 in Harbour Talbot.
Tata Steel UK has offered to pay £550m into its now-closed dismiss scheme and give the fund a 33% stake in its UK business.
It means Tata disposition no longer have any responsibility for the pension scheme.
Future pension grows for current and retired steelworkers will be less under the new scheme — but there settle upon be no reduction in the lump sums they have already built up.
All fellows of the British Steel Pension Scheme (BSPS) will now be invited to conveyance to the new scheme.
They will also have the option of transferring into the superannuation protection fund (PPF) — the pension lifeboat — although they could consume more money.
Thousands of workers voted to back the deal in February.
Koushik Chatterjee, Tata Sword’s group executive director, said it had been a long and detailed method but this was an «important milestone in Tata Steel UK’s journey towards a sustainable and long-lasting future».
He added: «Considering the continued challenges in the global steel perseverance as well as the uncertain global politico-economic environment, the regulated apportionment construction (RAA) presents the best possible structural outcome for the members of the BSPS and for the Tata Stiletto UK business.»
Trade unions Community, GMB and Unite said: «For over a year our associates have feared for their security in retirement and this announcement pinches to bring that uncertainty to an end.»
But they added that members had been «hellishly disappointed at the unacceptable lack of communication» in recent months.
«This has to become immediately,» said the unions in a statement. «The company and the trustees must call to mind they are dealing with people’s long term future, their autobiography savings and their family’s financial security; it is vital members are gospel all the support that they need.»
Analysis from Simon Gompertz, BBC News personal finance presswoman
There is bitterness, likely to be followed by bewilderment.
Current and former steelworkers entertain watched their pensions being tampered with.
Next they on be faced with what could be a mind-boggling choice about what to do.
The British Stiletto Pension Scheme trustees say the new scheme with trimmed benefits choose be better for the vast majority than falling back on the Pension Safe keeping Fund.
But there are a lot of variables to consider: the age at which they want to hit the sack, the tax-free lump sum they can get, or whether they should accept the ravishing sums being offered to exit the scheme entirely.
It is very signal, the trustees admit, that members make an informed choice after fetching advice «including from an independent financial advisor».
But who will pay for that? The trustees won’t, and the Allowances Regulator won’t make them.
There will be leaflets and written report, but many workers will feel they are being left on their own to on one of the most important financial decisions of their lives.
Lesley Titcomb, chief executive of The Pensions Regulator, said: «We do not assent to to these types of arrangements lightly but after several months of strong negotiations in this case, we believe that it is the best possible effect for everyone involved in what is a very difficult situation.»
BSPS trustees chairman Allan Johnston answered: «It is the best outcome that could be achieved in the circumstances.»
Aberavon MP Stephen Kinnock said it was notable to remember that the agreement to the pension changes was contingent upon huge investment from Tata.
«It is vital that Tata follow washing ones hands of on their £1bn investment plan to ensure Port Talbot and downstream purlieus remain at the leading edge of 21st Century steel-making,» he said.
The UK Government remarked it would «continue to work closely with the sector to help safeguard a viable long-term future for the UK steel industry.»
Analysis by Brian Meechan, BBC Wales role correspondent
Tata had been warning for years that its business in the UK was call of threat.
It blamed falling steel prices as well as high vigour costs and business rates in the UK compared to many other EU countries.
Allowances was not one of the main reasons it gave for its concerns but it clearly was an issue.
The company bid to radically reduce the benefits its scheme provided but that was seen off with the foreboding of strike action by unions.
Less dramatic changes to pensions were granted instead.
When Tata announced it was selling its UK operations, it started to see influence in areas it had long been complaining about.
The UK government introduced fiscal help for heavy energy using industries like steel.
EU taxes were placed on cheap steel imports from China and Russia.
Then as you can see from the map above, prices started to rise; the Port Talbot plant fitted more efficient and the drop in the value of the pound made selling abroad easier.
The dispute over pensions took many twists along the way, incorporating an aborted attempt to change the law for the Tata scheme that many texture would set a dangerous precedent.
What has now been agreed instead is enthusiastically unusual.
Tata will still have some responsibilities all over the huge £15bn pension fund but it will now be expected to stand on its own two feet with an injection of £550m to aide plug its black hole and a third stake in the company’s UK operations for the new move.
It paves the way for a merger deal between Tata Steel and its German challenge, Thyssenkrupp.
Whether that deal is actually good for the future of Harbour Talbot is still a hotly-contested point.
The pension changes along with the tooling of issues like energy costs and cheap imports put Tata’s UK craftsmen — which are now largely based in Wales — on a more solid foundation.
Despite that, the world is still making far more steel every year than it needs.
China nevertheless has newer steelworks as well as lower labour and energy costs, so wishes remain fiercely competitive.
Tata’s promised future investment in Anchorage Talbot is tied to its performance.
The immediate danger may have receded but there are stilly many challenges ahead.