But the agents selling Eydon Hall, which lies just 11 miles from Banbury, do not expect such a huge sum to deter a string of bidders for this rare and elegant home.

The 18th century Grade I listed property has come onto the market following the death of its former owner, world renowned race horse breeder Gerald Leigh.

Jim Bryant, from estate agents Bidwells which along with Knight Frank is selling the estate, told the Banbury Guardian: "It is extremely unusual for a property like this to come onto the market.

"We wouldn't expect anything else like this to become available this year. I would envisage a whole host of bidders coming forward – from horse breeders to international millionaires."

Sitting in an elevated commanding spot among 600 acres of land with completely unspoilt views over the South Northamptonshire countryside, Eydon Hall retains all its original features.

It was built in 1791 after the revered Francis Annesley purchased Eydon Lodge for £6,600.

He demolished the lodge and rebuilt the new classical villa using ironstone from the original building together with stone quarried on the estate.

The estate has been home to a small number of families, only four in the last 100 years.

Unusually, each facade of Eydon Hall is different. Architect James Lewis was reluctant not to design an ostentatious main entrance and so the column lined portico unusually sits at the back contrasting with the classical simplicity of the front.

The western facade features a semi circular bow which includes a perfectly oval sitting room complete with a curved door.

There are nine bedrooms, seven bathrooms and five main reception rooms. It has four levels, the basement almost a complete floor in itself and the upstairs servants' quarters disguised from the outside by balustrades.

Decoration includes elaborate hand painted Chinese wall paper in one of the bedrooms which remains in beautiful condition despite being hundreds of years old.

There are formal gardens, a croquet lawn, parkland and a hard tennis court. Two gate lodges, a cottage and three staff flats provide extra accommodation.

And, as home to Mr Leigh's thoroughbred breeding operation, there is a magnificent stable yard, a range of stud buildings, a further 22 loose boxes and extensive paddocks.

The estate is available as a whole or in three lots. Mr Bryant said: "I wouldn't be surprised if potential buyers were prepared to take on the entire estate.

"There are many wealthy buyers who are constantly looking for the perfect property and this kind of property does not come along very often."