For me it was…
Telephone interview - competency based
Why Barclays? Why the discipline you chose? Then some standard competency questions.
If successful, 1st round assessment centre
More in depth interview, still competency based, commercial awareness question also, another numerical reasoning test, a written study and a short presentation on your findings, what I’d call an abstract logic test (fastrack) and a group exercise.
If successful, 2nd round assessment centre (final one for me)
Another interview, much more laid back, asking about your experiences in uni & jobs, what you like, where do you think you’d fit in, gives a bit more info about the work you’d do. After that 2 case studies where you work through problems with an assessor (or 2).
To be honest though they tell you what to expect in each case as you progress through the process.
Good luck with your application.