Oxbridge Mathematics

Oxford Mathematics

For information on how to apply: http://www.maths.ox.ac.uk/study-here/undergraduate-study/how-apply

For information about the MAT (mathematics admissions test), including past papers and solutions: MAT TEST

Pre university sample problems: https://www.maths.ox.ac.uk/study-here/undergraduate-study/practice-problems

Cambridge Mathematics

http://www.maths.cam.ac.uk/undergrad/admissions/

STEP information

Link to some recommended reading: Recommended reading

Maths Helper has some great resources and tough practice questions