I would strongly recommend learning animation before applying to any of the decent animation courses in the UK because it would be highly unlikely that you'd get in with out that work in your portfolio - I know I don't let in applicants to one of my degrees (the 2D Animation one) without evidence of good animation in their portfolio. If you're not applying to a good animation course then you'll be fine without that skill.
You should try animation before applying to university to make sure you actually like it. Lots of people like watching animation, they like drawing a character... but until you've animated one, and gone through the entire process of linework, fill, backgrounds, editing, sound etc and realised that a minute of animation has 750 -1500 drawings in it (per character!) only at that point will you know that you like it (if you get through that and are still smiling and having fun then yes you should totally apply; you obviously want to be an animator and your fate is sealed). I would advise learning if you like animating before you spend a lot of money discovering that animation is really hard and you don't like it! Universities won't give you a refund... and you can find out if you like animation at home for free before spending a lot of money - there is free 2D animation software like Krita or even the 2D part of Blender (Grease Pencil) that you can use to find out if you like the subject! Get a copy of Richard Williams' The Animator's Survival Kit and start practicing!
By the way if you are thinking of studying 3D Animation or VFX or 3D Games Art then you won't necessarily need 3D Animation in your portfolio (although it's great if you do have it), having examples of 3D models you've made would be fine if you're not an animator - but do check with individual universities; some may have odd requirements.
Oh yes and no matter which type of animation degree you apply to, please practice drawing!