You can see details of student working conditions from p.93 of the Tier 4 Home Office casework guidance here.
Conditions that allow work
Work is permitted for student visa holders under the following conditions:
• part-time during termtime (up to a maximum of 20 hours a week)
• full-time during vacations, including the period before the course starts
• on a work placement as part of the course
• full-time as a postgraduate doctor or dentist on a recognised foundation programme when permission has been - granted for this course type
• as a Student Union Sabbatical Officer for up to 2 years when permission has been granted for this purpose
Additionally, students must not:
• fill a full-time permanent vacancy other than a recognised foundation programme and all other requirements are met or where they are filling a post as a Student Union Sabbatical Officer
There’s more info in the Home Office Student Sponsor guidance from p.57 here.
Definition of term time for UG and PGT students
For undergraduate and taught post-grad students, ‘term-time’ is defined by the terms dates of the student sponsor (usually listed on the institutions website). In the absence of printable confirmation of term dates a letter of confirmation would be required from the student sponsor of the relevant term dates.
PhD and Doctoral students have a continuous academic year
For post-grad research (incl. doctoral) students the academic year is considered continuous, so they are restricted to 20 hours per week year round, until they have ‘completed’ their course. The definition of completed is either awarded (evidence with a letter/certificate), or where they have fully submitted with no further corrections (evidenced by a letter from the sponsor/supervisor).
Vacation time for PhD students to enable full time working
Additionally, post grad research students may be granted a period of ‘vacation’ by their supervisor, and they are permitted to work full time during any vacation period. They would need a signed letter from their supervisor confirming they’re on vacation and the exact dates of the period to be considered as vacation.
The 20 hour per week limit cannot be averaged
The 20 hour per week limit covers any given week and can’t be averaged out over a longer period. It also covers all work the student might undertake in any role, so if they work 8 hours per week in one post, they can only work up to 12 per week in another.
Contact for GTAs who have questions about their visas of sponsorship
The university’s Tier 4 student sponsor license is managed by Student Services. King’s students should contact them if they have any queries relating to their visa/sponsorship: https://self-service.kcl.ac.uk/category/?id=CAT-01006