Brigadier Brian Jeffery is Commander 1st (UK) Signal Brigade and Chief G6 Allied Rapid Reaction Corps. After commissioning in 1999 Brigadier Brian's early service was in Germany and the UK including tours at 16 Signal Regiment, the Army Training Regiment (Lichfield) and at 30 Signal regiment. His final tour as a Captain was the staff officer responsible for the trials of specialist surveillance and CIS capabilities.

After promoting to Major and completing initial staff training and the Battlespace Technology MSc, he served in MOD Head Office as the staff officer for C4ISR urgent capability requirements, commanded 12 Mechanized Brigade Headquarters & Signal Squadron (228) and was Deputy Chief of Staff of 11 Signal & West Midlands Brigade. On promotion to Lieutenant Colonel, he completed the Advanced Command and Staff Course, served as SO1 J6 Operations in the Permanent Joint Headquarters (PJHQ) and commanded 21 Signal Regiment.

Promoted to Colonel in 2020, Brian became Deputy Head of Capability of the C4ISTAR Branch within UK Strategic Command and served in PJHQ as DACOS J3 SCORPIUS in PJHQ for six months in 2022. Following a deployment to Baghdad as Senior Advisor Cyber Security within NATO Mission Iraq, Brian was Chief of Staff of the Programmes Directorate in Army Headquarters before completing the Higher Command and Staff Course in 2025.