Business and philanthropy
Oppenheimer was chairman of Pniel's Ltd, the New Vaal River Diamond & Exploration Company, and Blaauwbosch Diamonds Ltd, and managing director of Lewis & Marks Ltd of Holborn. His brother, Sir Ernest Oppenheimer, was also heavily involved in the diamond industry.
In July 1917, Oppenheimer established a scheme for training disabled soldiers in diamond cutting at Brighton, England. The Bernard Oppenheimer Diamond Works (National Diamond Factories Ltd) opened on Lewes Road/Coombe Road (north side) on 17 May 1918. It was mainly paid for by Oppenheimer himself and by Lewis & Marks. In 1920 it also opened branches in Cambridge, Wrexham and Fort William. By 1921 the works, including a second building on the opposite side of Coombe Road, employed about 2,000 men who were referred to it by the Ministry of Labour. New men received six months training, during which they were paid a maintenance allowance by the government, and were then virtually guaranteed employment at a good wage. The factory had a well-equipped clinic to provide ongoing care for the employees, many of whom were amputees or otherwise severely disabled. The business did not do well and closed in 1923, but reopened later the same year. It finally went into receivership in 1924.
In 1917 he purchased Sefton Park estate, Stoke Poges, Buckinghamshire, where he lived till his death. During that period, he and his near neighbour, Walter A.Judd bought land which included Gray's Monument in Stoke Poges, a memorial to the English poet, Thomas Gray, so as to save it for the public. In 1925 Gray's Monument and Gray's Field were handed over to the National Trust.
For his work with the disabled, Oppenheimer was created a baronet in the 1921 New Year Honours. He died suddenly six months later at the age of 55. He married Lena Straus, with whom he had six children.
- Brighton Gazette, 18 May 1918
- Rigby,Lionel. Stoke Poges:A Buckinghamshire Village through 1000 years(2000) Phillimore.p.67 & 112. ISBN 781860771316
- National Trust Gray's Monument & Gray's Field Retrieved on 17 January 2021
- "No. 32178". The London Gazette (Supplement). 31 December 1920. p. 2.
- Geni, 23 May 2018
- Burke's Peerage. 1949.
- Obituary, The Times, 14 June 1921