This sham castle folly was built to ornament the ‘beautiful grounds’ of the house which is now called Thornborough Hall, on the edge of Leyburn in the Yorkshire Dales*. Part of the gardens was developed for housing in the 20th century, but there is still plenty of interest if one sets off to explore the woodland behind the hall.
Ralph Riddell married Molly, or Mary, Thornburgh in 1769, and in 1774 she inherited the Thornburgh family lands in Leyburn. A substantial house is shown on maps of the town from around this date and the Riddells, although Northumberland based, made this their Yorkshire seat.
An exact date for the folly has yet to be found and sadly the earliest maps don’t feature the grounds. But it was certainly there by 1822 and may be even earlier, possibly part of a programme of landscaping by Ralph and Molly Riddell after the estate came into their hands.
The present house was remodelled and extended for Francis Riddell in the middle of the 19th century, and it seems to have been renamed Thornborough Hall around this time. The architect was Joseph Hansom, he of Hansom cab fame, who worked on the family’s Northumberland seat, Cheeseburn Grange, at around the same date.
The sham castle is built against a bank, in what appears to have been a quarry, and a path leads up the back to reach the upper viewing platform. Sadly, the little hexagonal lookout tower which once stood on the roof has gone and the roofline, which was probably once castellated, has been neatly, but inauthentically, coped. Tree growth means the view is now lost, as is the access to the roof which has been blocked off for the usual reasons of health and safety. The two sturdy towers are in pretty good condition, thanks to some remedial work by Richmondshire Borough Council in the late 1990s, and the arched entrance is barred to deter those who find building fires in follies irresistible. Denied this pleasure, the local youth have been forced to loiter outside, leaving cairns of cans and crisp packets as their calling card.
The Riddells principal seat remained Cheeseburn Grange, but they maintained Thornborough until the early years of the 20th century, although it was let for periods. In 1919 Bulcote School for girls moved from Scarborough to Thornborough Hall, and was based there until the estate was put up for auction in 1934. The Yorkshire Post suggested that were there no interest in the house for use as a ‘private hotel or some other institutional purpose’ then it could be demolished as it was ‘ripe for development’. Happily the house survived this threat and has been used as council offices since the 1950s, although part of the grounds has been lost to housing.
In 1974 Barbara Jones called the folly ‘one of the prettiest and most peaceful little sham castles in England’, and it remains a delight that is well worth seeking out.
* Thornborough was formerly called The Grove, or Leyburn Grove. Names of the principal houses in Leyburn have changed frequently: the present Grove House is no relation to the building being discussed here. For Thornburgh read Thornborough, Thornbrough, Thornboro…