Submit application on website, attach cv. Once accepted, complete the online assessment within 3 days of receiving the invite. (Maybe Psychometric style and situational judgment) British Airways do change the assessment types so bare in mind.

Starts with a group of about 25 people, then have to do a height and reach test accompanied by reading out a script to one of the interviewers to prove your english speech. Then have a group task with half the group to see how you interact with others. Then half the group are sent home and the other half go through to individual interviews.