Hestercombe was occupied by the military during the Second World War, although the Honourable Mrs Portman, Edward's widow, kept the Lutyens-Jekyll garden for her private use.
In 1944 Hestercombe was passed to the Crown Estate in lieu of Portman death duties, but Mrs Portman continued to live at the house until her death in 1951.
The Crown Estate leased the house and the formal garden to Somerset Fire Brigade in 1953. By this time, the garden was falling into disrepair, and over the following years Lutyens' stonework, which was the responsibility of the landlords, slipped gradually further into dilapidation.
The garden, looked after by fire brigade gardener Albie Allen from 1956 to 1971, remained well tended, but over the years the original planting scheme devised by Gertrude Jekyll was all but lost and the borders became gradually more overgrown.
Informal investigation and research for a possible restoration of the garden began in the late 1960s. William Mount (known as ‘Bil'), principal landscape architect for Somerset County Council from 1962 to 1974, headed up a small landscape team within the county architect's department that had responsibility for the design and maintenance of the grounds of council buildings, including those of the fire brigade.
Bil was shown round the gardens by Laurence Fricker, a lecturer in landscape architecture who had grown up locally. Mr Fricker had long campaigned for better protection for both the Lutyens-Jekyll garden and the 18th-century landscape garden created by Coplestone Warre Bamfylde in the Combe, a steep-sided valley to the rear of the house. He had brought many people to see the site over the years, including Frank Clark and Graham Stuart Thomas.
It has often been stated in articles and publicity about Hestercombe that the Great Plat was at risk in the early 1970s of being covered with tarmac.
Bil and members of his team recall there being such a proposal, but Leslie Johnson (chief fire officer from 1972) and other members of the fire brigade strongly refute the idea that this was ever suggested.
That the fire brigade was proud of, and cared for, the garden is borne out by the words of the chief fire officer from 1960 to 1972, Aubrey Leonard Bullion (known as ‘Len'), who in an unpublished article of 1968 wrote: ‘I have become bewitched by the artifice of those who created the magic of Hestercombe gardens...the last 10 years of my life have been enriched by my association with Hestercombe, which is a joy at any time of the year.' 
Hestercombe House in 1975
The Great Plat in 1972/3
Discovery of the original Jekyll plans