You should have, or expect to obtain, a 2:1 Honours degree in a relevant science or engineering subject (eg Biology, Biochemistry, Biomaterials, Biomedical Science, Biomedical Engineering, Chemical Engineering, Chemistry, Environmental Science, Materials science).
Holders of bachelor's degrees will normally be expected to have achieved 55% - 60% or higher for 2:1 equivalency, or 50% - 55% for 2:2 equivalency depending on the awarding institution.