The Unite union has called off a strike planned for 8 July so further talks can take place over the future of the UK’s largest steel works at Port Talbot in Wales.

Owners Tata had threatened to bring forward the planned closure of both remaining blast furnaces the day before the strike, citing safety fears due to a staff walkout.

Unite’s strike action was called to the dismay of other unions who feared that it would accelerate the closure of blast furnace number four which was not due to be shut down until September.

The Community and GMB unions had hoped that would give them time for more negotiations to extend the life of the remaining furnace with a potentially new government in place.

On Thursday Tata said it would close both furnaces within days unless it could “safely and stably operate” them during the strike.

Then it wrote to all three unions, offering to begin new talks if the strike was called off.

The firm says the talks will not renegotiate the existing plan but will focus on future investment opportunities.

The government has already promised the firm a £500m grant towards the development of a new £1.25bn electric arc furnace which recycles scrap metal, is less energy intensive, but requires far fewer staff.

The closure of both furnaces at Port Talbot would cost 2,800 jobs. But extending the life of one of them would save 2,000 of those jobs if the remaining blast furnace was left on until the new electric arc furnace has been built on the site, which could take up to three years.

Sources close to the matter told the BBC that Unite had given Tata the perfect excuse to shut down early, accelerating job losses.

But Unite officials rejected that, saying their action “helped focus minds”, and are claiming a victory of sorts over the news that further talks will take place after the election.

However, in a letter to unions from Tata – seen by the BBC – it is clear the company had already agreed to further talks after the upcoming election.

Alun Davies, national officer for the Community union, said: “The truth is Tata never walked away from those discussions, and at our last meeting on 22 May all unions agreed to conclude the negotiations and put the outcome to our members.

“Community would welcome resuming those discussions, but we regret that zero progress has been made since 22 May.”

Officials from other unions say that Unite has achieved “nothing but chaos and have cost their members money” – a reference to an earlier overtime ban which Unite called without the agreement or knowledge of the other unions.

Union officials acknowledge that there is no guarantee that Tata will agree to extending the life of one furnace beyond its scheduled shutdown in September.

But officials have expressed hope that if Labour wins the election, its manifesto commitment to invest £2.5bn in the steel industry could help secure a lifeline.