By the time the 6th Earl had inherited Kenwood at the beginning of the 20th century he had plans to sell the land off for building. But the First World War scuppered this, followed by a vigorous campaign to protect the land by the newly set up Kenwood Preservation Society - there is a plaque to the man who spearheaded the successful protest, Arthur Crosfield, on the terrace.
Money was raised to buy nearly 140 acres for the public which became known as Kenwood Fields and South Kenwood but the house, estate buildings and 74 acres were bought by the art collector and philanthropist Edward Cecil Guinness, 1st Earl of Iveagh.
Although Edward Cecil Guinness wanted the house as a setting for his art collection he never lived to see the paintings hung. But, philanthropic in death as in life, he bequeathed the house and parkland to the public and in July 1928 King George V formally opened Kenwood to the public.