Dennis began his career as an officer in the British Army, specialising in international crisis management and counter-terrorism operations. His military service included leadership roles in intelligence and covert operations. Notably, he served as Deputy Director of the UK's Defence Crisis Management Centre, commanded a unit engaged in anti-terrorist operations, and directed the Army Centre for Anti-Terrorism Training.
His distinguished operational leadership earned him the OBE, awarded by HM Queen Elizabeth II. Dennis further honed his international expertise by attending the Italian Army's esteemed senior officer course and serving as the UK Liaison Officer to the Italian Army.
After his military career, Dennis initially transitioned to the private sector as head of security for an Italian family behind one of the world's leading fashion brands. He later founded a consulting firm specialising in crisis management and resilience, delivering services to top-tier companies and government agencies worldwide. His private sector work has involved leading consulting teams for global clients such as Avon Cosmetics, Bank of New York Mellon, Deutsche Bank, Diageo, Dubai Ports, Eurostar, HSBC, Investec, John Lewis, Linklaters, Lloyds Banking Group, Royal Mail, Swiss Re, and many others.
Dennis has overseen numerous crisis training and simulation programmes addressing scenarios such as cyberattacks, reputation management, hostile takeovers, pandemics, natural disasters, financial market volatility, and terrorism. In the public sector, his leadership has included providing cyber-readiness support to a UK Intelligence Agency, facilitating financial sector-wide exercises in the UK and Singapore, and testing crisis plans for organisations such as the Irish Aviation Authority, the UK Cabinet Office, and UK central government departments.
Dennis exited his consultancy through a sale to pursue academic and research interests, focusing on the factors that enable individuals and teams to sustain resilience and high performance under challenging conditions. He earned an MSc in Applied Positive Psychology, a field dedicated to studying the conditions, behaviours, and processes that enhance resilience and performance across people, teams, and institutions.
In an unexpected career twist, between 2021-2024 Dennis was chief executive of one of the UK's largest not-for-profits delivering wildlife conservation programmes in the UK and Africa. Having completed the task of leading the organisation through COVID and setting it on the path to a sustainable future, Dennis has returned to his crisis management roots. He is the founding Senior Research Fellow at the newly-established Centre for Sustainable Business at UCL in London. UCL is a world top-10 university.
In his consulting work, Dennis is the founder and CEO at Ardenna, an AI-native firm focused on the application of AI to empower organisations to achieve optimal resilience.
Outside of his professional commitments, Dennis enjoys trekking in remote mountainous areas. Each year he takes part in a 300-kilometre self-supported challenge trek across the Scottish Highlands. He is also an enthusiastic downhill skier, embracing the sport with more passion than proficiency.
