Brigadier Dennis commissioned into the Royal Marines in September 1997. His initial Commando and Fleet time saw service across the globe from the High North to the Far East. Like so many Royal Marines at the time there were multiple tours of Afghanistan, with a highlight being Officer Commanding 3 Commando Brigade’s Communications Squadron, overseeing Task Force Helmand’s tactical and strategic communications and IT links (2008/9).
Staff jobs, interspersed with staff training at ICSC(L) and ACSC, have included time in DE&S, Navy HQ, PJHQ and MOD Main Building, predominantly focused on Capability, Finance and Operational support roles. However, C4ISR positions have dominated his career, especially in the Joint space. Initially specialising as an RM Signals Officer, he has undertaken roles with Commando Helicopter Force as well as teaching the Royal Corps of Signals. On promotion to Lt Col he was in C4ISR Joint User involved in C4ISR Policy, JEF and CJEF CIS activity as well as providing C4ISR advice to the 4th floor in MOD Main Building. This was followed by being the Military Assistant to CEO ISS (now Defence Digital), gaining a detailed understanding of all Defence Information System capabilities and procurements. As a Colonel he oversaw the Navy Portfolio in FMC during the Integrated Review 21, before driving digital transformation in PJHQ supporting C4ISR requirements for Operations as J6 DACOS Information Exploitation and Engineering.
He assumed the role of ACOS J5 and Customer Services within Defence Digital in November 2023 on promoted to Brigadier RM.
He is a rugby enthusiast, watching rather than playing these days. He is also a keen cyclist, swimmer, hill walker, hockey player and occasional rock climber.