It was designed by architect David Bryce for John Campbell of Possil (see Carter-Campbell of Possil) in the Scottish Baronial style, and completed in 1858. Torosay is surrounded by 12 acres (4.9 ha) of spectacular gardens including formal terraces laid out at the turn of the 20th century and attributed to Sir Robert Lorimer. The castle and gardens used to be open to the public, being linked to the Craignure ferry terminal by the Isle of Mull Railway. At the present date (February 2012) The Castle is for sale, the railway has been closed down and the trains have been sold.
The garden's Statue Walk is made up of 19 statues in the style of Italian sculptor Antonio Bonazza. The statues were acquired by then-owner Walter Murray Guthrie from a derelict garden near Milan and shipped to Scotland for next to nothing as ballast in a cargo ship.
John Campbell of Possil sold the castle and the estate to Arburthnot Charles Guthrie, a wealthy London businessman, in 1865. It served as his "getaway" and must have been ideal for that purpose, as the castle has over 60 rooms and is surrounded by an estate of over 12 acres (0.049 km2). The current owner is now the sixth generation of the Guthrie family to live in the castle. Following the sale of Guthrie Castle out of the Guthrie family, Torosay is now generally acknowledged as the seat for Clan Guthrie. However, the Castle was sold in 2012 and the Castle and its Gardens were closed to the public in the summer.
The Campbell of Possil coat of arms on the south elevation of Torosay Castle incorporates three bugles (horns). These were taken from the armorial bearings of John Campbell's third wife, Elizabeth Williamson, daughter of Donald Horne, but were never matriculated by the Lord Lyon of Scotland.
The novelist Angela du Maurier, older sister of Dame Daphne du Maurier, is said to have spent some time residing at Torosay after her close companion Olive Guthrie (Great Grandmother of the present owner) was left a widow by the death of her husband Walter.Other visitors during the 1930s included Winston Churchill and the King of Greece.[which?] Over the last few years a dynamic "Head Of Gardening" has been in situ,Duncan Travers with over 35 years experience has been taking the wonderful gardens of Torosay through a cultural change which will provide pleasure and opportunity for generations to come.
In July 2008 the then oldest bottle of Veuve Clicquotchampagne was discovered inside a sideboard in Torosay Castle. The 1893 bottle was in mint condition. It is believed to have been locked inside the dark sideboard since at least 1897. The champagne is now on display at the Veuve Clicquot visitor centre in Reims, France, and regarded as "priceless".