Entering the imposing front door to the magnificent Great Hall, visitors step back in time and see the Doric columns of a Roman Basilica, which realised Adam’s instruction to create ‘a palace of Graeco-Roman splendour’.

The decorative stucco work and great beams of the ceiling reflect the pattern of the black and white marble floor. Statues of Roman nobles gaze down from their pedestals and the hall’s focal piece, a replica of Valadier’s bronze ‘The Dying Gaul’, commissioned by the 1st Duchess of Northumberland, holds pride of place at the top of elegant steps leading to the Ante Room.

Illustrating Robert Adam’s intention to “parade the conveniences and the social pleasures of life”, every aspect of the State Dining Room with its ornate Corinthian columns and marble statues of Ceres and Bacchus representing food and drink, offers the experience and enjoyment of entertaining on a grand scale.

Above the imposing fireplace designed by Joseph Rose, is a marble panel by Luc-Francois Breton of the Three Graces, the daughters of Zeus. The fine clock in the corner of the room was acquired by the 2nd Duke and made in England by Swiss clock maker Benjamin Vuilliamy. Its pedestal contains musical pipes which used to play lively tunes. Gilded candelabras sit on ornate Adam designed pier tables, adding to the opulent atmosphere. Remnants of the state dining table, which ran the length of the room, can still be seen, hidden in a cleverly disguised cupboard. With the dining table stored away; one could make room for dancing and much revelry. The State Dining Room is still used for many celebrations today.

The Long Gallery was planned by Adam for the particular delight of the ladies. On entering the Long Gallery visitors will see a false bookcase on the right which is in fact a door leading to the south lawn.

Ladies and other guests could promenade the length of the gallery, which measures 136ft (41.4m) and is highlighted by a decorative turret room at either end.

Adam’s design used 62 Corinthian pilasters, gilded and painted, along with classical trailing stucco mouldings, to replace the heavy Jacobean panelled walls. The gallery’s colour in Adam’s day was bright pink and blue, and these original colours have been uncovered after a conservator’s investigation. A green colour wash was added by the 3rd Duchess in the nineteenth century, giving the softer hue you see today.

Roundels of the Percy family lineage run the length of the room, with portraits of Dukes and Duchesses on one side and the Earls of Northumberland on the other. Modern family photographs now sit on Demi-Lune pier tables designed by Adam.

As with all of Syon House, the Long Gallery has seen much history and it is said that Lady Jane Grey was offered the crown in the gallery in 1553.

The principal staircase leads to the bedroom corridors remodelled by the 3rd Duke in the 1820s and 1830s.

Two bedrooms on view here are furnished in an Edwardian style and were used as a nursery for the current Duke and his siblings when the family would come to Syon for the spring and summer seasons. The landing outside these rooms is called the Nursery Passage. Continuing down the passage to the east front of the house you will find the richly decorated State Bedrooms of young Princess Victoria and her mother the Duchess of Kent. The 3rd Duchess Charlotte Florentia was given the coveted role of being Princess Victoria’s official governess, and in doing so prepared the young princess for her future role as Queen.