David is currently a Director with Able Security Consultants. Prior to this, he served almost 40 years within UK law enforcement, with 30 of these as a police officer and 9 years as a CTSA (Counter Terrorism Security Advisor) supervisor. His areas of specialism include counter terrorism protective security, critical infrastructure protection, insider risk, and personnel security,

In 2019, he was appointed as an Expert Security Witness to the Manchester Arena Public Inquiry and worked on the first part of the Inquiry, relating to the security for the arena. He concluded this role in 2020.

David has previously consulted with the Interpol CBRNE Terrorism Prevention Unit, Airpol, and the OSCE Action Against Terrorism Unit. He was lead author in the OSCE guidance manual on Protecting Critical Infrastructure from Terrorist Attacks.

David is a Principal Member of the NPSA approved Register of Security Engineers and Specialists, and is a Chartered Security Professional. He has been published in journals internationally on Insider Threat and terrorism related issues.

He also serves as an Honorary Professor with Glasgow Caledonian University, and a Visiting Professor with Coventry University.