Colonel William N. Jones bought the estate from Major William J. H. Hughes in 1919. He was an industrialist who gained his title of Colonel in the First World War when he was placed in charge of the Ammanford Home Guard.
Col. Jones never lived in the Middleton estate, leaving a caretaker, Mr Hilbert Lloyd, and his family to live in the hall, farming pigs. The rest of the estate, Col. Jones rented out to tenants.
Unfortunately, in 1931, the hall “was reduced to ruins by fire” (Carmarthen Journal, November 6th, 1931), leaving nothing but the walls standing. The property was mortgaged off, and in 1934 Carmarthenshire County Council bought the remains of the hall, the surrounding park lands, and all buildings that had been built on the estate throughout the years, and all lands known as The Middleton Hall Estate, from Barkley’s Bank for £7,500. Twenty years after the fire, the hall was torn down
The council converted all of the outbuildings, including the old servants’ block (the only element of the mansion that was not destroyed in the fire), and built new farmsteads, creating seven starter farms in order to encourage young people to work in the agricultural industry. One of these farms was Waun Las, which is now a nature reserve within the National Botanic Garden. These farms became a thriving community through until the 1990s.
In 1978, the remains of the estate and Paxton’s creations caught the interest of local walkers, one of which was the aunt of Welsh artist, William Wilkins. After doing some research into the history of the estate and with the guidance of Millennium Commission, Wilkins made an application to create the first botanical garden in Britain in 200 years.
The Great Glasshouse was built to the southwest of the Paxton’s relocated hall, and the Garden of was officially opened by the Prince of Wales 24th May 2000.