When the great folly builders of the 17th and 18th centuries were erecting statement buildings on the high points of their estates, they can little have known how useful they would be to the Board of Ordnance. The ‘Principal Triangulation of Britain’ was a trigonometric survey, begun in the late 18th century, which by determining precise coordinates of significant landmarks would enable highly accurate mapping. The main landmarks used were church spires, but ‘other remarkable objects’ were picked, and in the first decade of the 19th century over 50 towers, temples, obelisks, summer houses and follies made it into this category.
Brizlee Tower* stands high on Brizlee Hill, near Alnwick, and overlooks Hulne Park, a detached pleasure ground close to the Duke of Northumberland’s principal park at Alnwick Castle. It was built in the late 18th century as a prospect tower and eye-catcher, and also as an object to be visited on a drive from the castle through Hulne Park. The park was designed by ‘the inimitable Brown’, aka Capability, working with local engineers and designers, and was also home to the ruins of mediaeval Hulne Abbey, embellished and repurposed by the Duke and Duchess as a banqueting house, pleasure garden and menagerie for exotic pheasants.
Few follies can be said to have directly contributed to coastal erosion, but one example can be found in the lovely little village of Hunmanby, near Filey. Early in the 19th century Humphrey Osbaldeston, of Hunmanby Hall, took stone from the rocky coastal outcrop called Filey Brigg, and used it to erect this rustic entrance arch.