Drake’s Island, just 600 yards from Plymouth, was used as a military defence for hundreds of years – with 18th-century cannons still in position and included in the sale.

It takes less than 10 minutes to reach by boat and once on land there is military history everywhere.

From old barracks to artillery batteries complete with shell shafts and underground gunpowder stores.

“It has over 2,000 years of history – the first recorded building is 1135,” current owner and local businessman Morgan Phillips told Sky News.

“It was its nuclear deterrent of its day, that’s probably why the Spanish armada never came here!”

Mr Phillips bought the island in 2019 for £6 million and has worked on securing consent for a 43-bed hotel.

He gives guided tours to groups.

“Plymouth is trying to become a destination – it’s getting there, it’s a long way forward with that. What we really need is the island to be taken forward and someone who has got the budget to be able to do that,” he explained.

The island is named after Sir Francis Drake – who set sail from it to circumnavigate the globe in 1577.

It has no fixed guide price but renovation costs are estimated at around £25m.

Ali Rana from property consultants Carter Jonas is leading the sale.

“The proposals include for these [outbuildings] to be converted into bedrooms and one of the things the owner has been thinking about is using this as a wedding venue where the guests would stay there and potentially put a restaurant, café at the end. It’s one of those opportunities where with some vision you could really create something special,” Mr Rana said.

Any new owner may not be alone though, with reportedly 15 resident ghosts – all former military men.

“If you believe the mediums who come out here… they’re all British squaddies,” said Mr Phillips.

“They are here to protect us. That’s what they did when they were alive and that’s what they’re still doing!

“I’ve seen enough to say stuff happens here that I can’t explain. But all of it is really nice,” he insisted.