In the 1850s, the estate was bought by Thomas Henry Allen Poynder, and passed on his death to his brother, William Henry Poynder.
On his death, the estate passed to his nephew, John Dickson Poynder, who on the death of his uncle Sir Alexander Collingwood Thomas Dickson became the sixth baronet Dickson of Hardingham Hall.

Sir John became MP for Chippenham in 1892, and a Member of London County Council from 1898 to 1904.
He also served in the Second Boer War as aide-de-camp to Commander in Chief Paul Methuen, 3rd Baron Methuen, winning a DSO in 1900.
He then chaired the Islington Commission.
Appointed Governor of New Zealand in 1910, he was raised to the peerage as Lord Islington.
After two years he returned to become first Under-Secretary of State for the Colonies and then Under Secretary of State for India.

From the start of his ownership, Baron Islington began to remodel Hartham Park.
The house was remodelled and the grounds were landscaped by Harold Peto, including a Dutch water garden, subsequently largely overbuilt in a 1960s redevelopment.
Hartham also became a focal point for political and recreational life in North Wiltshire, with records showing numerous stays for his friends Winston Churchill and Prince Arthur, Duke of Connaught and Strathearn, the third son of Queen Victoria who enjoyed the local game shooting.
In the 1850s, the estate was bought by Thomas Henry Allen Poynder, and passed on his death to his brother, William Henry Poynder. On his death, the estate passed to his nephew, John Dickson Poynder, who on the death of his uncle Sir Alexander Collingwood Thomas Dickson became the sixth baronet Dickson of Hardingham Hall.
Sir John became MP for Chippenham in 1892, and a Member of London County Council from 1898 to 1904. He also served in the Second Boer War as aide-de-camp to Commander in Chief Paul Methuen, 3rd Baron Methuen, winning a DSO in 1900. He then chaired the Islington Commission. Appointed Governor of New Zealand in 1910, he was raised to the peerage as Lord Islington. After two years he returned to become first Under-Secretary of State for the Colonies and then Under Secretary of State for India.
From the start of his ownership, Baron Islington began to remodel Hartham Park. The house was remodelled and the grounds were landscaped by Harold Peto, including a Dutch water garden, subsequently largely overbuilt in a 1960s redevelopment. Hartham also became a focal point for political and recreational life in North Wiltshire, with records showing numerous stays for his friends Winston Churchill and Prince Arthur, Duke of Connaught and Strathearn, the third son of Queen Victoria who enjoyed the local game shooting.
Hartham Park