You also have to take into account the difficulty of the degree you choose to do, and the quality of the university you want to study at.
At Durham Uni they required evidence of recent learning, to access their foundation year course. So I simply had to pass my access course, to be guaranteed a place on the foundation year.
I chose to study Physics at Durham Uni, and there is no chance of me entering the first year of a Physics degree there with an access course alone.