The 4ha garden near Biggleswade in Bedfordshire was in such a state of disrepair that it was placed on the English Heritage "Heritage at Risk" register.
However, The Shuttleworth Trust can request for the garden to be taken off the register thanks to the HLF-funded 18-month project.
The garden was created by Lord Robert Henley Ongley in the early 1800s and was sold to Joseph Shuttleworth in 1872. It is located behind the Shuttleworth Collection aviation museum and is one of the best examples of landscaping from the Regency period. The landscape boasts bridges, urns and arches.
Luton-based Chris Garrand Associates produced the garden's management plan, while Chris Burnett Associates was the project's landscape architect.