Oversley Castle, which is perched above the local landscape just outside Alcester, has for decades been a familiar sight to motorists and passers-by.

Now they will be able to look beyond the entrance gates when it is opened to the public between September 11 to 20 .

The sneaky peek round the property, which was also the site of a Royal scandal during the 19th century, is being offered by new owners Paul and Anna Harvey.

They have plans, once the public’s curiosity has been satisfied, to turn it into five individual residences and convert the ancient outbuildings, barns and even a swimming pool into homes.

As part of the project, a circular four-storey turret will be added to the main house, replacing a tower that was demolished back in the late 19th century. A square tower that still remains has 360 degree views across seven counties.

Oversley’s long history goes back to the time of King Offa. Offa’s Ley means Offa’s pasture. This was later transcribed as Oversley.

The earliest records for the castle date it from the 11th century. But evidence of earlier settlements in the area has been uncovered, including a Bronze Age axe head and Roman and Celtic coins dating back to 30 BC.

In Norman times there was probably a motte and bailey-style castle on the site but this was replaced around 1238.

In the 16th century, the Manor of Oversley had passed into the hands of Henry VIII’s chief minister and advisor, Thomas Cromwell, whose wily ways made gripping viewing in the TV adaptation of Hilary Mantel’s Booker Prize-winning Wolf Hall.

Thomas fell from favour after arranging the unsuccessful marriage between the King and Anne of Cleves and was eventually executed for treason and heresy.

Sir George Throckmorton of Coughton Court, a neighbour and rival of Cromwell’s, made the most of his misfortune, purchasing Oversley in 1542 for £777 9s 2p.

In the 19th century, the Prince Regent used to enjoy assignations at Oversley with the Marchioness of Hertford, wife of the Marquess of Hertford, whose country residence was Ragley Hall.

In a breathtaking display of Royal cheek, the Prince asked the Marquess to upgrade the castle at his own expense to make it more romantic for their liaisons.

A rather more recent owner, David Grieg, founder of the Grieg’s grocery chain, a rival to Sainsbury’s in the first half of the 20th century, carried out a major remodelling in the 1930s, transforming it from a rather forbidding fortress into a grand country house.

This next stage in Oversley’s history will see the creation of 14 residences, ranging in size from one to five bedrooms, set in 65 acres of grounds. Work on them is expected to be completed next year.

Warwickshire-based Paul and Anna are old hands at restoration having worked on several local manor houses: 17th century Netherstead Hall, Oldberrow Court, Studley Old Castle and Gorcott Hall.

Paul said: “Oversley Castle is without doubt the most ambitious project that Anna and I have undertaken.

“Like many people who live in Warwickshire, we had often seen Oversley Castle from a distance because of its prominent location 350 feet above sea level and directly opposite Ragley Hall. However, beyond the entrance gates remained a mystery because it was a privately-owned home.

“When the chance came to buy it from a family who had owned it for nearly three decades, I decided to seize the opportunity.”

Work has already started on the first phase, the conversion of seven period barns, and these are now for sale.

Three of them are Grade II listed with a former threshing barn boasting a vaulted ceiling that dates back to the Tudor period.

Another property – The Pool House – is being created from the former swimming pool and is partially set into the hillside .

A fully-furnished show home can be viewed during viewed during the opening week.