Most forms of medical degree require applicants to take a separate admissions test. Depending on your applications you will have to take one or both tests.
A smaller number of medical schools, including Oxford, Cambridge, Imperial , UCL, Brighton & Sussex, Leeds and the Royal Veterinary College require students to take the BMAT (Bio Medical Admissions Test). The BMAT test has three sections; general problem-solving, application of science and maths (a level equivalent to GCSE/IGCSE standard is required) and essay writing, including ethical issues. You must register for the BMAT test before submitting your UCAS application and the results of the test will then be sent directly to the medical schools you apply to. Further information can be found here http://www.admissionstestingservice.org/for-test-takers/bmat/about-bmat/
Whereas some medical schools say that students should sit these tests without revision, we believe in preparing our students thoroughly and leaving nothing to chance. You should make sure that your school or colleges is willing to assist you to ensure that you are familiar with the tests and get as much practice as possible.
There are a number of graduate entry medical schools and several of these require applicants to take a different test called GAMSAT – the Graduate Medical School Admissions Test. See here for more information https://gamsat.acer.edu.au/
The UKCAT (UK Clinical Aptitude Test) is required by the majority of medical schools, as well as most dental schools. The UKCAT is not a test of medical science, but covers elements such as reasoning skills, decision analysis and situational judgement. The UKCAT test must be taken BEFORE the UCAS application is submitted and the results stated on the application. There is no pass/fail mark but the scores are taken into account by admissions staff and there may be a minimum score required for interview (this will vary from year to year depending on the calibre of candidates)
Follow this link to find out about UKCAT http://www.ukcat.ac.uk/