Early reports indicate a deal to end the bitter jobs dispute at the Total-run Lindsey oil refinery, which has led to unofficial walkouts by thousands of workers across the country.
The agreement follows talks between union leaders and employers of contract staff at the North Lincolnshire site. Unions said the deal involved the reinstatement of 647 workers sacked for taking unofficial strike action and would be put to the workers on Monday.
Total said it was pleased that "a positive conclusion" had been reached. In a statement on Friday, a spokesman for the company said:
"Total is pleased that the contract companies and the unions were able to reach a positive conclusion at talks last night.
"We expect this means that the contractors will be able to get back to work as soon as possible and get the project completed on time and with no further disruption or additional costs."
The Lindsey workers went on strike on 11 June after a sub-contractor cut 51 jobs. It is thought those people will also be offered the chance to return to work.
The dispute sparked wildcat sympathy walkouts involving thousands of workers at power stations and oil and gas facilities across the country.
Les Bayliss, of the Unite union, said:
"Following hours of detailed negotiations we now have proposals for a return to work which will be recommended by the stewards to the workforce.
"The employers have agreed to reinstate the sacked workers but the details have to be put to the workforce first."
Another union, the GMB, has recommended workers accept the deal and end the dispute.
The negotiations were adjourned after five hours in London on Tuesday and resumed in Manchester on Thursday afternoon. Total was involved in the talks after previously refusing to take part.
On Friday morning, staff at some of the sites affected by sympathy strikes began to return to work. Hundreds of workers at Sellafield in Cumbria and Longannet in Fife, who had downed tools, voted to end their walkouts. Other sites affected by industrial action following the Lindsey dispute included Drax and Eggborough in North Yorkshire, Stanlow in Cheshire, Aberthaw in south Wales and Didcot in Oxfordshire.
The sacked Lindsey workers had been planning to stage a demonstration outside the Paris headquarters of Total next week.
They had been employed on a project known as HDS-3 to build a new site alongside the existing Lindsey plant.
Total fears the dispute has set the project back by months and that as a result it will cost an extra 100 million euros (£85m). It has not yet commented on the outcome of the talks.
However, the Socialist Party has declared the strike "a stunning victory" in which all the workers' demands have been met. They also reported that "The 647 dismissals have been withdrawn, the 51 redundancies rescinded and all employees have been guaranteed a minimum of four week's work - what they would have got if Blackett and Charlton had taken them on - i.e. as much work as is probably available."