Initially, a walk-through CV and why I am interested in working for the Environment Agency, followed by a brief introduction to the interview structure and guidance, and then a competency-based interview similar to the application.

Pretty straightforward, mine was via teams. Questions mainly focused on competency (usually the same as the competency questions on the online application), and I was also given 15min for a technical questions. As long as you follow the STAR technique you'll be fine, I would recommend looking at the STAR dictionary, it shows you the descriptions and how you should answer for each competency.