It is the private island said to have inspired the cult British horror film The Wicker Man.

But isolated Tanera Mor proved less scary, more the perfect family getaway, for the Duke and Duchess of Sussex during their week-long visit to Britain last month, The Mail on Sunday can reveal.

Harry, Meghan and their children, Archie, seven, and five-year-old Lilibet, are believed to have stayed for two days on the remote island in the Inner Hebrides.

As well as experiencing its stunning views, abundant wildlife – including otters and seals – and sandy bays, they are understood to have enjoyed a relaxing boat trip around its coastline aboard Rita, a vintage Clyde puffer.

The 800-acre island is owned by hedge-fund tycoon lan Wace, 63, who has managed to stay friends with both William and Harry even after the brothers’ relationship soured.

The royals are believed to have previously visited Tanera Mor, the largest of the Summer Isles, in north-west Scotland.

Mr Wace, who is worth around £600 million, bought the island nine years ago for £1.7 million. Since then, he has spent up to £100 million creating an idyllic retreat for up to 60 guests.

As well as planting 100,000 trees, restoring a dozen properties and reviving skills such as bee-keeping, the tycoon has also laid three miles of roads.

All visitors to the island are expected to follow its strict environmental ethos.

Mr Wace – a Tory Party donor – fiercely guards the privacy of his guests, according to locals.

They say that staff who work on re-wilding projects there are sent off the island the day before celebrities arrive and only return the day after they have left.

The only way to get on to the island is to launch from jetties Mr Wace owns – and visitors need permission to use them.

The Sussexes are thought to have arrived on Tanera Mor on July 8 – the day after Harry lost his High Court privacy case against the publisher of the Daily Mail and The Mail on Sunday.

They are likely to have stayed in one of the two areas on the island offering extreme privacy – the North and South Ends.

Croft cottages there have been renovated to the highest standard and are described as places to ‘recover’ and grow more resilient.

Despite the lengths Mr Wace has gone to safeguard his guests’ privacy, The Mail on Sunday can reveal that the Duchess may have accidentally revealed her family’s location after posting 12 photos on her personal Instagram account, under the title ‘Summer Holiday’.

One picture – a moody shot of hills and water – appeared very different from the other images and so became the target of much speculation.

The Mail on Sunday soon identified the exact spot in the Scottish Highlands in which it had been taken – next to Loch Droma on the A835 Inverness to Ullapool road, just 25 miles from Tanera Mor.

One local in Achiltibuie, the nearest mainland village to the island on the Coigach peninsula, told The Mail on Sunday: ‘We all know when somebody important is coming over because the workers are all told to go away for a few days, while (Mr Wace] has guests who want privacy.

‘There’ve been rumours Harry has been there in the past, and William has been there.’

Another said: I’ve heard Harry and Meghan were on the mainland side, as well as on the island.

‘There are electric bikes over there for guests to use and sometimes people staying there bring them on to the mainland.

‘They didn’t get there from Achiltibuie, so must have gone the other way from Ullapool on the fast boat. There’s a lot of work that’s happened since [Mr Wace] bought it – he’s worked on all the old buildings to renovate them.

‘He will have improved the roads as well. By all accounts it’s very high-end accommodation. He’s spent a fortune.’

Mr Wace and his former wife, model Saffron Aldridge, 58, have long been friends with the Duke and Duchess of Sussex and accompanied them to a performance of Cirque du Soleil at the Royal Albert Hall in 2019.

A spokesman for Mr Wace did not respond to our request for comment.