According to Alan O'Rourke, who leads H&K's Defence portfolio, the answer is surprisingly simple:

"Engagement."

With more than 25 years' experience working across the Defence Estate, Alan has seen significant changes in everything from accommodation standards and sustainability requirements to the increasing complexity of modern facilities.

As part of our Defence Infrastructure series, we asked him to share some of the lessons, challenges and memorable moments that have shaped his career.

Swipe through to read his insights.