Energy giant BP is considering selling the UK's largest oil pipeline.

The Forties pipeline carries around 40% of British oil, transporting it from the middle of the North Sea to an onshore terminal in Aberdeenshire.

BP is considering selling the 100-mile pipeline to London-based Ineos, which already co-owns Scotland's only crude oil refinery at Grangemouth.

A BP spokesman said: "BP can confirm it is in discussions with Ineos regarding a potential sale of the Forties Pipeline System.

"We remain committed to communicating openly with staff and our stakeholders as soon as we are able, and as commercial confidentialities allow, if any deal is confirmed or agreed."

In January, BP announced plans to sell part of its stake in the Sullom Voe oil terminal.

The £68m deal with EnQuest also includes a 25% share in the Magnus field and a number of pipelines.

BP last year scrapped plans for a £500m gas processing facility near Sullom Voe which would have created 330 jobs, while cutting about 20% of its UK workforce.

About 120,000 people whose jobs were linked to the oil and gas sector in the UK are thought to have been made redundant since the slump began in early 2014.

Companies including BP, Shell and Wood Group have made significant cuts since the value of a barrel of oil plunged from a high of $110 in June 2014 to under $30.

The price now sits at around $50, but a lack of investment threatens the future of the industry.

The Queen opened the Forties pipeline in 1975, ceremonially "launching" the North Sea.

The Unite union has raised serious concerns about the potential sale following disputes with Ineos in 2008 and 2013, when the company threatened to close Grangemouth amid a dispute with staff.

Unite Scottish secretary Pat Rafferty said: "Our members at BP will have major concerns about the possibility of becoming employees of Ineos, a company with a clear history of attacking our members' pensions, as well as their terms and conditions, in order to maximise profit.

"If a sale does go ahead, we will fight to protect our members in every way we can, and Ineos should work with us to allay their fears.

"There is also a wider issue of economic power. The Forties Pipeline System carries a massive amount of the UK's oil. Grangemouth is the one of the country's major refineries.

"Both of these pieces of vital national infrastructure could soon be effectively in the hands of one man. That is an incredible amount of power.

"It's not so long ago that both Grangemouth and the Forties pipeline were owned by all of us, and operated by a nationalised British Petroleum with a responsibility to look at what was good for the country as a whole, not just what was good for a small group of wealthy individuals."

"Unite doesn't believe that is good for workers or good for the country," he added.

"Our members will be listening closely to the views of our governments both at Westminster and Holyrood."