Green’s Dictionary of Slang

1. a civil servant.

2003

Guardian 4 Dec. 🌐 These postings were interspersed with stints as a ‘Whitehall warrior’ on various desks at the Foreign Office in London.

2. an officer in the services who has been seconded to administrative rather than active duties.

2002		‘Obituary – Field Marshal Sir Nigel Bagnall’ at BagnallVillage.com 🌐 Field Marshal Sir Nigel Bagnall began his career as an infantryman in the Malaysian jungle, spent his middle years trying to make military sense of Nato’s nuclear-dominated strategy on the north German plain, and ended up a Whitehall warrior who fell foul of Margaret Thatcher.
2003		Guardian 2 May 🌐 ‘Politicians like him, and that’s probably more important than battle experience nowadays,’ said Major Charles Heyman, editor of Jane’s World Armies. ‘I would not describe him as a Whitehall warrior, but he understands what politicians are after and can speak their language.’.