Cook's Castle was built around 1174 by Sir Richard Worlsey who was also responsible for the lovely Appuldurcombe House. The castle is nothing more than a modem turreted tower, said to have been built by Sir Richard in order to enrich the view from the windows at Appuldurcombe House.
It was deeply embowered in trees and was a favoured place for picnic parties. Additionally, for anyone who climbed it, there were enchanting views of Appuldurcombe House as well as the Worsley Monument and the Free Mantle Gate. To the east, Shanklin and Sandown were visible and in the distance the white cliffs of Culver.
"Those who continue on the path all the way from Shanklin will reach Cook's Castle by bending to the right soon after the Worsley obelisk comes in sight, and then entering a wood, by a stile at the south-east corner."
- Jenkinson's Practical Guide To The Isle of Wight (1876)
Fortunately during the 1840s, George Brannon decided to engrave the then crumbling folly as one of his island points of interest. It shows, as can be seen above, a fine looking folly that would have been a very enticing landmark to visit.
Over the next hundred years it can only be assumed that the building's crumbling walls became a useful pile of stone rubble for recycling into other estate projects. Its final demise was sealed by the 16th August 1940 spitfire Mk 1 - X4016 crash.
The plane was piloted by flying officer H.P.Connor from 234 Squadron, who, after tangling with a Messerschmitt Bf109 had to bail out leaving the spitfire to spiral down and crash next to the ruins. It caused a large explosion and substantial damage over the area of the folly.
Today on St. Martin's Down the position is approximately marked (as no physical remains of the folly exist) by a stone cairn engraved with the words "Site of Cook's Castle".