Computer Science


The Computer Science Tripos (CST) used to have a variety of options in the first year, but these have recently been streamlined, and it is now only possible to apply for one CST programme.  Whereas in earlier years it was possible to spend some of the first year studying Mathematics, Physics or another Natural Science subject, this is no longer the case . All CST students are now admitted to follow what is locally known as “CST 75%”.

This programme of lecture courses, the most popular choice since its introduction, suits students who wish to concentrate their studies on Computer Science to the maximum extent possible, without incorporating material from related subjects. A student following CST 75% will spend 75% of their first year preparing for three papers on various aspect of Computer Science and the remaining 25% of their time completing a Mathematics course that is held in common with other subjects.

Optional Fourth Year

The CST course is a three-year BA degree, however, it is possible to apply to continue studying Computer Science into a fourth year, provided a sufficiently high standard is achieved in the third year examination. The course then leads to the MEng degree in addition to the BA achieved in the third-year examination. The course then leads to the MEng degree in addition to the BA achieved in the three-year course.  If necessary – for example in dealing with your funding body – it would be wise to indicate that the length of the course is four years, or three/four years, to allow for all possibilities.

Further information on the CST Tripos

Please see for further information hosted by the Department of Computer Science and Technology website.  In particular, you may find information there on the detailed structure of later years of the CST.

CST in Trinity

Trinity’s Directors of Studies in Computer Science are: Dr Sean Holden, whose research interests include machine learning, Bayesian inference, and artificial intelligence; Professor Frank Stajano, who focuses on security, privacy, human factors and entrepreneurship; and Dr Neel Krishnaswami, whose research interests lie at the intersection of program verification, programming language design and logic, semantics and type theory.  In addition, Trinity has two Post-Doctoral Teaching Assistants in CST, Dr Jonathan Woodruff (processor design) and Dr Ekaterina Kochmar (natural language processing), who assist us in providing undergraduate supervisions.

Student rooms provide network connections allowing access to email, the web and all major computing facilities around the University. There are also well-equipped computer rooms which provide access to scanners, laser printers and where the bulk of the machines can be re-set to run either Windows or Linux.

Interview and written tests

Candidates will sit a pre-interview written test before being shortlisted for interview.  This is called the Cambridge Test of Mathematics for University Admission (CTMUA) and details, including sample test papers, can be found here:

Those invited to Cambridge will then have a 45-minute interview with two people, at least one of whom will be a Director of Studies.   Immediately before this interview candidates will sit a second test called the Computer Science Admissions Test (CSAT), and the interview will involve a discussion of their progress through the CSAT.  Detailed information regarding the CSAT, including advice on how to prepare and sample questions, can be found at

Please note that your performance in the written tests and interview will not be considered in isolation, but will be taken into account alongside the other elements of your application.

Preparatory on-line course

Before arriving in October successful candidates will be required to complete an online pre-arrival course.  Details regarding the organisation of this course will follow later in the admissions process.


Conditional offers for the CST will typically be A*A*A including Mathematics and two other science subjects (preferably Physics and Further Mathematics); we may also ask for a high grade in a relevant subject taken at only AS level.

Comparable conditions are set for those taking the IB and other school-leaving examinations.  The annual intake is normally between 6 and 8.

Teaching Staff

  • Dr Sean Holden
  • Dr Neel Krishnaswami
  • Professor Frank Stajano

Admissions Assessment

All applicants are required to take the pre-interview written assessment for Computer Science (CTMUA) at an authorised centre local to them (for a lot of applicants, this will be their school/college).

Assessment format

  • Paper 1: Mathematical Thinking multiple-choice questions. (75 minutes, no calculator)
  • Paper 2: Mathematical Reasoning multiple choice questions. (75 minutes, no calculator)

You must be registered in advance (separately to your UCAS application) to take the assessment – the registration deadline is 15 October 2019. Please note that open centres may set an earlier deadline for accepting entries, and it is your responsibility to check if this applies at your centre. Your assessment centre must register you for the pre-interview assessment; you’re not able to register yourself. See the written assessments page for information about assessment centres and registration.

The pre-interview written assessment for Computer Science will be taken on 30 October 2019. Please check the Cambridge Assessment Admissions Testing website for scheduled start times.

Please note that your performance in the pre-interview assessment will not be considered in isolation, but will be taken into account alongside the other elements of your application.


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