What happens if you fail your first year of university?

Fortunately, I've not and have managed to secure a 1st, however, I know many students in my course who have failed one or multiple modules. Some have retaken the modules (but it's capped at 40%) during the summer and awaiting their new (but capped) results.

From what I've been told, we need to pass all 6 modules in order to qualify for second year. So, I'm just curious to know, what happens if a student fails to gain over 40% on a module, and fails to meet the criteria set? Will they have to retake, transfer or possibly leave altogether?

I suppose all universities will have different views on the matter, but generally speaking, any idea what consequences students will begin to face if they've failed to pass their modules?

Anyone got any information on this? Whether it be past experience or things you've heard, I'm quite curious to know. Thanks guys.