Thank you for your reply. Unfortunately, it's not possible to do a double major in England. There are 'joint courses' which is basically doing 50:50 = maths:physics; but university that I'm going to doesn't have maths and physics joint course. Also, I'm not fond of idea of doing half of each.
I'm in my last year of school and starting a mathematics degree at a British university this Autumn. I've always liked mathematics, especially 'pure' side of mathematics. I love poofs and always enjoyed solving puzzles and brainteasers for fun. Some of my favourite topics of maths are geometry...