Usual suspects (in no particular order, not exhaustive!) - Oxford (PPE), Cambridge, UCL,LSE, Bath, Bristol, Warwick, Durham, Nottingham, Manchester.. etc. That is for Economics. Most require you to have a good Maths A-level grade and typical entry requirement is A*AA-ABB. This is partly because it is a very popular course.
So it depends on what grades you expect to achieve and what subjects they are in. Look at the UCAS web site and judge which course/uni you think would suit you best. Lists course requirements etc.
http://www.ucas.com/students/coursesearch/
It is generally better to do an Economics degree then a post-grad masters specialising in finance/business.
From personal experience of Uni (I have a lot and didn't like most of it), I would say choose a course that you will enjoy and that you will be motivated on and go and look round the Unis and choose the one that you feel fits you best. If you pick one based on reputation and hate it, your over all grade and uni experience is unlikely to be good. However, if you're happy, you'll work hard and succeed in whatever you choose to do. There are also a lot of snadwich courses available that will provide valuable work experience for when you enter the job market when you graduate.
Good Luck