Not true unfortunately, though most locals believe it! The 1902 Richmond, Petersham & Ham Open Spaces Act related only to a transfer of ownership on the Surrey (Richmond) side of land from the Dysart family to the then council.
However there is also the 1902 LCC General Powers Act, a mixed bag of powers, whose Section IV Purchase of the Marble Hill Estate, Twickenham allows the LCC to purchase Marble Hill and adjacent land ‘to preserve the view’ – but only by agreement.
Also to provide boat houses . . This power has now passed, via the GLC, to LBRuT, I think but this needs checking. The folder for both in the Local Studies Centre at Richmond Old Town Hall is 32/03/30 #187 centre no. #L337.72:026.
‘ . . A Deed of Covenant was entered into by Richmond Borough Council, Twickenham Borough Council and Surrey, Middlesex and London County Councils in 1930. The terms of the deed were designed as far as possible to preserve the view from Richmond Hill by restricting the future development of the land to certain limited areas only. Compensation was paid to the then owners of the land for granting the right to enforce these restrictions . . ‘
The right to enforce the covenant now rests, I think – wth LBRuT.
See also: • The History of Orleans Gardens