[4] The grotto is set into the northeast face of a hill, and comprises an entrance hall and a series of six chambers extending over 65 feet (20 m) into and 30 feet (9.1 m) below the chalk hillside, together with air shafts, light wells and connecting passages.
Its construction may have taken several years and was completed by John Scott, an 18th-century Quaker poet who inherited Amwell House from his father in 1768.
Scott also had other romantic features built in his garden, including an octagonal gazebo on the hillside above.
[6][7] The grotto was acquired by East Hertfordshire District Council in 1974, and was restored in 1990–91 by the Ware Society.
The architect for the restoration was James Howley and the project manager David Perman, Hon.