It was a wedding present from the Queen that fell into rack and ruin and became the last symbol of Prince Andrew's failed marriage to Sarah Ferguson.
The once grand former home of the Duke of York became mired in controversy seven years ago when he sold it to Kazakh tycoon Timur Kulibayev for £15 million – £3 million more than the asking price – and criticism grew as it was left to rot.
Now The Mail on Sunday can reveal that plans to demolish the much derided 'Tesco-style' mansion in Berkshire and replace it with a similarly lavish house have been thwarted – by bats in the rafters.
Despite winning permission to bulldoze Sunninghill Park a year ago, its new owners have just had to apply for fresh permission to continue with the project, and find alternative accommodation for the rare bats which are protected.
According to documents submitted to the local council by architects, a survey found at least 100 bats flapping around the building or emerging from holes in the roof.
The species include common pipistrelles, soprano pipistrelles, noctules, brown long-eared, mouse-eared and Leisler's.
Experts recommended that alternative roosts be built in nearby trees before demolition work on the dilapidated building can finally begin.
The property – dubbed SouthYork because of its resemblance to the house on the ranch in the US television soap Dallas – boasted 12 bedrooms with en suite bathrooms, a marble-floored hallway, offices, a cinema, stables, billiards room and swimming pool.
Now it is a shadow of its former self, with broken windows and boarded-up doors.
After its sale in 2007, a year after Sarah Ferguson and her daughters Princesses Beatrice and Eugenie moved out, the house was left derelict.
It prompted speculation that Kulibayev, the billionaire son-in-law of Kazakh president Nursultan Nazarbayev, had bought it only to win the Prince's friendship during his time as a UK trade ambassador.
But Buckingham Palace insisted the sale was 'a straight commercial transaction'. Kulibayev acknowledged ownership only after a newspaper investigation revealed he had used offshore companies to make the purchase.
It was suggested that his former mistress, millionairess socialite Goga Ashkenazi – a close friend of Prince Andrew – was instrumental in securing the sale.
The bat survey, which is part of the application submitted to Bracknell Forest Council, was commissioned by HOK International, which is an agent for the owners Unity Assets Corporation, though it is not clear who will live in the new house.
An initial assessment in June concluded: 'This is a suspected roost of moderate quality', and added: 'Because the number of tiles is so large there are several gaps which bats could roost under.'
It recommended that two further bat 'emergence' surveys should be carried out at dusk, and further observations were made in August and September. Local authority planners will now consider the report before making a decision next month.
Designed by Sir James Dunbar-Nasmith, SouthYork was given to Prince Andrew by his mother after his marriage in 1986. Its new owners are planning to bulldoze the property to make way for a six-bedroom house boasting a gym, pool and staff accommodation.
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