BT uses SOARA framework for interview process. Usually a panel of 1 HR rep and 1 technical. Prepare a situation that demonstrate a challenge you have faced and overcome. Be prepared to admit mistakes but have answers to how you would do things differently and prove learning. Not a drastically difficult interview but ensure you also have a backup SOARA and be prepared to elaborate on the finer points.

It was simple based upon my past experiences with other companies. You just need to be confident and be precise with all the questions they ask. Don't need to give them a comprehension based answer.