Multiple stages, a phone call to form an initial assessment followed by a video call with the hiring manager involving some more in depth questions about why I want to work for BSI and what I expect to be doing and team leader and an in person tour and interview with the people I'd be working with from the team leader and their boss. There was great communication throughout the process with regular updates and I was offered an alternate role to the one originally applied for based on my skills and background. Everyone was very friendly and helpful and the whole experience was positive.