Jeremy Hosking is in negotiations to buy Kinloch Castle on Rum, a 19th-century pleasure palace built for a Lancashire industrialist, which has been owned by government agency NatureScot and its predecessors for 65 years.
Previously run as a hostel, the deteriorating castle has been closed to the public since 2015, with the building now requiring repairs of between £5 million and £10m to save it from further ruin.
NatureScot said the proposed sale to Mr Hosking, who ultimately wants to use the castle as a hotel, signalled a sustainable future for the castle free from the public purse.
But Isle of Rum Development Trust (IRDT), a community landowner that holds much of the island, is furious it has been excluded from talks over the sale given the castle sits at the heart of the main island settlement.
A key issue is the main road to the castle, with Mr Hosking, whose fortune is valued at £385m, ideally wanting the route, which falls partly on trust land, as private access.
A spokesman for Mr Hosking said a “meeting of minds” had to be reached over the sale. The spokesman said: "There is no indication of Jeremy pulling out of the purchase of Kinloch Castle. He has met with the island community once and that doesn't preclude him from a further meeting.
"He acknowledges this will have to be a meeting of minds at some point. NatureScot has been quite upfront that this is a perfectly sustainable and sensitive plan and has encouraged all parties to rally round.
"This is also Jeremy's view, that this does have to be a collective effort, but if Kinloch Castle needs saving, there needs to be as much positive engagement as protest."
IRDT called for the process to be “rolled back” to allow talks to open up with other potential buyers given the proposal was pitched to Mr Hosking as a private sale.
The trust met with Lorna Slater, minister for green skills, over their concerns, with the Green Party MSP allegedly apologising to islanders for the situation reaching this stage. The trust will meet with the Scottish Land Commission on Monday, with a meeting with NatureScot to follow.
Steve Robertson, development officer at IRDT, said NatureScot had disregarded the Government’s own community land-owning agenda over the sale.
He said: "NatureScot could have handled this a lot better and we are very disappointed we are having to drag them to the negotiating table. That shouldn’t be the case for Rum and it shouldn’t be the case for any community in Scotland.
“For a public body that has been working with us for the last 12 years, there is no excuse. It is Nature Scot we are upset with and not the owner.”
A spokeswoman for NatureScot said: "We will continue to work constructively with the community to deliver new arrangements for the castle and provide long-term benefits to the Isle of Rum. NatureScot advises that negotiations continue with the prospective purchaser of Kinloch Castle. Any changes to the vehicle access rights in front of the castle will require the agreement of the Isle of Rum Community Trust.”