The Right Honourable The Lord Derwent CBE
Derwent in 1968
Minister of State for Home Affairs
In office 23 October 1963 – 16 October 1964
Monarch	Elizabeth II
Prime Minister	Sir Alec Douglas-Home
Preceded by	The Earl Jellicoe
Succeeded by	Alice Bacon
Minister of State for Trade
In office 6 September 1962 – 23 October 1963
Monarch	Elizabeth II
Prime Minister	Harold Macmillan
Preceded by	Alan Green
Succeeded by	The Lord Drumalbyn
Member of the House of Lords Lord Temporal
In office 13 January 1949 – 2 January 1986 Hereditary peerage
Preceded by	The 3rd Baron Derwent
Succeeded by	The 5th Baron Derwent
Personal details
Born	(1901-10-26)26 October 1901
Died	2 January 1986(1986-01-02) (aged 84)
Political party	Conservative

Patrick Robin Gilbert Vanden-Bempde-Johnstone, 4th Baron Derwent CBE (26 October 1901 – 2 January 1986), was a British peer and Conservative politician.

Derwent was the younger son of Hon. Edward Henry Vanden-Bempde-Johnstone, younger son of Harcourt Vanden-Bempde-Johnstone, 1st Baron Derwent. His mother was Evelyn Mary Agar-Ellis. He was educated at Sandroyd School then Charterhouse School. He succeeded as fourth Baron Derwent on the death of his elder brother, George Harcourt Vanden-Bampde-Johnstone, 3rd Baron Derwent, in 1949 and took his seat in the House of Lords. In September 1962, Derwent was appointed Minister of State for Trade in the Conservative government of Harold Macmillan, and when Sir Alec Douglas-Home became Prime Minister in October 1963 he was promoted to Minister of State for Home Affairs. He retained this post until the Conservative loss in the 1964 general election. He never held ministerial office again but served for many years as a Deputy Speaker in the House of Lords.

Lord Derwent married Marie-Louise Henriette Picard, daughter of Albert Picard of Paris, France, in 1929. He died on 2 January 1986, aged 84, and was succeeded in the barony by his son Robin Evelyn Leo Vanden-Bempde-Johnstone.