depends on your social life. and outside commitments
university is incredibly easy everything is done for you, it is very easy to get a 2 1 as lng as you do the work. someone who has done nothing all year can still pass they may not get a good grade but they still passed!!
it all depends on YOU!!
Well I dont know what a 2.1 is worth from Cambridge, but I would certainly be pleased to get one from Cambridge because personally I know the amount of work I need to do is a lot and therefore must be of value!
As others have said, it completely depends on the university. At Oxbridge you'll have to spend a fair amount of time studying, at somewhere like Leeds or Oxford Brookes you'll have to spend a fair amount of time in the pub. Enough said.