Basically you're marked on whatever your answer is to their question. You'll mainly be asked scenario type questions such as "When was there a time when you needed to act fast and deliver a plan?". It's not very intimidating as they just write down what you say and don't really pay attention to your nerves or lack of body language.

Interview was around 2.5 hours in total. Started with a group interview then 20 minutes on the shop floor shadowing a checkout colleague then finally a 1 to 1 interview with a manager.