The second son of Prime Minister Lord Rosebery, he represented Wisbech in parliament from 1910 to 1917 and served as Under-Secretary of State for Foreign Affairs in 1915 and as joint-Parliamentary Secretary to the Treasury from 1916 to 1917.

[5] In February 1915 he was appointed Under-Secretary of State for Foreign Affairs in H. H. Asquith's Liberal administration, but was not offered a post when the coalition government was formed in May of the same year.

[8] He died in November 1917 from wounds received in action at Gezer during the Sinai and Palestine Campaign while leading his squadron of the 1/1st Royal Buckinghamshire Yeomanry against Turkish positions on the Abu Shusheh ridge during the Third Battle of Gaza.

When news of the death of Primrose reached the UK, Prime Minister David Lloyd George paid tribute in the House of Commons on 19 November 1917, alongside his report of the death of Lieutenant General Sir Frederick Stanley Maude:May I be permitted before I sit down to utter one word of another who held an inconspicuous position in the Army but who was well known to all Members of this House.

He fell charging at the head of his troops, at the very moment of victory, and Members of the House will, I feel certain, join me in an expression of deepest sympathy with those whom he has left behind to mourn him.

Friend has referred, and which more particularly affects this House, a more familiar and well-loved face has passed from among us, and I only trust myself to say this, that there are few who can realise better than myself how much of hope and of promise there was for his future, and I am sure that his distinguished father and family will have the heartfelt sympathy of every Member of this House.Primrose is buried in the Ramleh Commonwealth War Graves Commission Cemetery at Ramla, in Israel.

[15] A further act of commemoration came with the unveiling in 1932 of a manuscript-style illuminated book of remembrance for the House of Commons, which includes a short biographical account of the life and death of Primrose.