You quite simply don't need a degree. At all. It may give you the edge on a mentored scheme but is that really worth 3/4 years of work and ten grand plus worth of debt?
You're much better off getting three good A levels (maths / science) and going from there.
That is, unless, you have loads of money and fancy 3 years of sleeping, and drinking.....
If you have to go to uni, go for a science / maths based degree.
EK