Immigration and visas

Academic Technology Approval Scheme (ATAS)

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An ATAS certificate is issued by the Foreign, Commonwealth and Development Office (FCDO). ATAS gives a student clearance to study subject areas where the knowledge gained may have application in the development or delivery of weapons of mass destruction (for example, some mathematics, engineering, technology or medicine courses). These are referred to by the government as “sensitive subjects”.


ATAS clearance is required to study these subjects at Essex if you are a PhD student and;

  • you are applying for a Student visa or,
  • you are applying for a Visitor visa or,
  • to register on your course where you have other types of limited leave to remain/immigration status (this applies to almost all immigration categories, including asylum)

You will not require ATAS clearance if you;

  • are a UK national or,
  • have Indefinite Leave/settlement in the UK or,
  • are a national of an exempt country or,
  • are studying a Masters, Postgraduate Diploma or Certificate with us.

It can take up to 30 working days for the FCDO to process your application for ATAS clearance and may be much longer in busy periods. You won’t be able to obtain a CAS to apply for a Student visa or apply for Visitor permission until you have the certificate so, make sure you allow plenty of time to apply.

Read all the guidance on the government website for more information.

Essex PhD students that require ATAS

Whether ATAS is required will depend on the CAH3 (Common Aggregate Hierarchy) code that applies to your course and your nationality. Your offer letter will outline whether your programme requires an ATAS certificate and include the CAH3 code. You can also use the government website to check if you need an ATAS certificate.

If ATAS is required, it will be a condition of your immigration permission. It is your responsibility to ensure that you adhere to all the conditions that apply to you, including that your ATAS clearance certificate is valid for the full duration of your studies. Breaching your immigration conditions is an offence and can have serious consequences for you.

Student immigration permission and ATAS

If you need to apply for Student immigration permission to study with us, you will be required to provide the university with a copy of your ATAS certificate to obtain a CAS (Confirmation of Acceptance for Studies) to start or continue your course and, will also provide it to UK Visas and Immigration when you make your application for Student immigration permission.

An ATAS certificate is valid for 6 months to make an application for Student immigration permission. If your course details or dates change or, your ATAS certificate will have expired before you submit your application online, you will need to obtain a new one before you can apply.

If we issue you with a CAS to study with us, we will be your Student Sponsor and you will have additional responsibilities to us and to the Home Office. Please read our student directory for more information about your responsibilities as a sponsored student (immigration).

Starting a new Essex course

The FCDO recommend you apply for ATAS 6 months before your new course is due to start.

To register and start your Essex course, you must provide our Admissions team with a copy of your ATAS certificate, before your course start date.

If you need to apply for Student immigration permission, the university will only issue you with a CAS (Confirmation of Acceptance for Studies) when we have received evidence of your ATAS clearance and all other checks have been completed.

If you are unable to obtain a new ATAS in time to start your course or have any other questions, please contact Admissions for advice.

Changes during your course

After you have registered and started your course, if there are any changes to your subject area or you need more time to complete your course, you must check if you require a new ATAS certificate and obtain clearance where applicable, otherwise you may not be able to continue your course. If you make an official request to change your course and it is agreed, you should be made aware if ATAS clearance will be required.

If you are a national of Australia, Canada, Japan, New Zealand, Singapore, South Korea or the USA and you applied for your current visa or immigration status before the 5th of October 2020, you will still need to apply for ATAS clearance if your course details change but not if you are applying for a new immigration permission as you will be exempt, please note that the government website will tell you that you do not require ATAS, this is incorrect, you should still sign in and apply.

A new ATAS clearance certificate may be required, in the following circumstances, if you are not exempt:

  • The course or research subject is one that requires ATAS clearance and;
  • You need to apply for Student immigration permission to complete your course or:
    • You will need to send us your new ATAS certificate before we can complete all our checks to issue you with a CAS (Confirmation of Acceptance for Studies). The FCDO recommend you apply for ATAS clearance 4 months before your immigration permission is due to expire.
  • You change your course, area of research or modules or your course end date is postponed by more than 3 calendar months but you do not need to apply for Student immigration permission.
    • You must apply for your new ATAS certificate within 28 days of the date the change is confirmed to you by the university in writing. This includes whilst completing your thesis, waiting for your viva or completing corrections inside the UK.

Before you apply for your new ATAS clearance certificate, you will require confirmation of your CAH3 code from the University, to obtain this you will need to do the following:

  • Firstly, contact your supervisor/department and agree a research statement that reflects the status of your current research, then when you have received the statement:
  • Email the International Services team to request the CAH3 code, you will need to include all the following information in your email:
    • Type “Request for a CAH3 code to apply for a new ATAS” in the subject heading or body of email
    • The full research statement that has been agreed with your supervisor/department
    • Your full name
    • Your Essex PRID and registration number

As soon as you have obtained your new ATAS certificate you must send a copy to our International Services team.

If you are inside the UK and are not able to obtain your ATAS certificate in time to apply for permission to stay longer under the Student route, you are likely to have to leave the UK but may be able to apply overseas.

If you are unable to obtain a new ATAS in time to continue your course, apply for permission to stay or have any other questions, please contact our International Services team for advice by completing our online enquiry form for current students.

How to apply

Before you apply, read all the relevant information on the government website including the “Guidance on how to apply for an ATAS certificate”.

If you are applying for an ATAS to start a new course the FCDO recommend you apply 6 months before you are due to start the course.

If you are continuing a course and require new ATAS to apply for Student immigration permission, the FCDO recommend you apply 4 months before your current immigration permission is due to expire.

Completing your application

Once you have established that you require ATAS clearance and have all the information you require, you will be able to sign in or create and account to complete and submit your ATAS application form online.

Proposed course of study section: you will input the paragraph describing your research topic that has been provided by your supervisor/department and is included in your offer letter. If you are continuing a course, the paragraph that you provided to our International Services team to obtain the CAH3 code should be used.

Course start date: If you are applying for ATAS for a course you have already started you will not be able to enter a date that is in the past, the FCDO have confirmed that you should put the date of the next working day as the course start date.

When you receive your ATAS certificate

You will receive your certificate via email, usually within 30 days however, it can take longer. Check your junk/spam folders regularly. When you receive it, you should read the government guidance online.

Check the details are correct and match your offer/research area the university provided. If there are any mistakes or inaccuracies contact the ATAS unit at the FCDO.

Send a copy to the relevant team at the university and let us know if you have reported any mistakes or inaccuracies to the FCDO:

If you have requested a CAS to apply for Student immigration permission, we will be able to continue with our processes and checks and if you are eligible, we will issue your CAS once these are completed. After you receive your CAS you should be able to apply for Student immigration permission.

If you are applying for a Visitor visa you will be able to submit your application provided you meet all the other requirements. If you are a non-visa national and will be applying for entry at the UK border, you must carry all the required supporting documents in your hand luggage, this includes your ATAS certificate.

Application issues

If you have not received the outcome to your application or, have an enquiry:

You can contact the FCDO by email, provided it has been more than 20 days since you applied.

If your application is refused:

You should read the government guidance and follow instructions you are given in the outcome if you wish to ask for a review. The university has no influence over the decision, but you must let us know:

You are very unlikely to be able to study with us as planned if your application is refused. If you have requested a CAS to apply for Student immigration permission this will not be processed.