MAT stands for Mathematics Admission Test and was formerly known as the Oxford Entrance Test for Mathematics degrees.
Oxford University and, from September 2013, Imperial College, London require students to take the Mathematics Admissions Test, MAT in addition to their A levels. The MAT is taken in November (of year 13) and the results are used to select candidates to invite for interviews at the universities.
For further information visit the Mathematics Admissions Test website, where you can obtain materials to practise for the test.
In September 2016 MEI and the FMSP are running a series of online sessions to help support students in their preparation for the MAT. This course is designed to equip students, with at least an AS Level in Mathematics or equivalent, to develop their mathematical thinking and so gain confidence in tackling these questions.
For further information please see the MEI website.