The owners of Scotland's only oil refinery have rejected a US-led approach about a possible bid for it months before its scheduled closure.
Sky News has learnt that a consortium said to be led by Robert McKee, an American energy industry veteran, wrote to Petroineos, the owner of the Grangemouth site, to express an interest in buying it.
The approach, which is understood to have been made earlier this month, was rejected by Petroineos, which is 50%-owned by the petrochemicals empire founded by the Manchester United FC shareholder Sir Jim Ratcliffe.
The consortium is understood to comprise The Canal Group, which is reportedly developing a green energy refinery in Texas, and Trading Stack, a Middle East-based commodities trader.
Mr McKee spent nearly four decades with ConocoPhillips, one of the biggest energy companies in the US.
Sources close to the situation said that Petroineos had rebuffed the offer in order to concentrate on a publicly announced plan to transform the century-old plant into a biofuels terminal.
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They added that the nature of the consortium's approach had raised questions about its access to financing and expertise in operating an asset of this kind.
The Grangemouth refinery, which employs about 450 people, loses about £200m annually.
Its other shareholder is the state-backed Chinese energy giant PetroChina.
The site is due to close next year.
A person close to the consortium insisted that its financing was robust and said it would assess the feasibility of building a new refinery elsewhere in the area.
They added that the consortium had had "positive interactions" with trade union officials, and believed that there was scope to rapidly make Grangemouth's refinery operations profitable.
On Monday, a spokesman for Petroineos said: "Since the Petroineos joint venture was formed 13 years ago, our shareholders have invested nearly £1bn in the refinery, only to absorb losses of £600m.
"Last week, the refinery lost £385,000 on average each day and we expect to lose more than £150m in total during the course of this year.
"We have not received any credible or viable bids for the refinery."
A spokesman for the consortium declined to comment.