The only essential GCE A level for admission to Cambridge to read for the Computer Science Tripos is Mathematics. Further Mathematics and Physics are both useful.
When the new A and AS levels are available, Mathematics will again be the only essential A level. Also desirable will be a physical science (Physics, Chemistry or Geology) at A level and Further Mathematics at AS level if not taken at A level. Candidates for admission will be encouraged to take the extension paper in Mathematics.
Those wishing to go on to Part IB Computer Science in their second year should take either the 50% option of Part IA of the Computer Science Tripos or the Computer Science option of Part IA of the Mathematical Tripos. The 25% option of Part IA of the Computer Science Tripos is principally intended for those who plan to continue with Natural Sciences in their Part IB year; it is not a suitable preparation for Part IB of the Computer Science Tripos.