Does this count as term-time for the purpose of authorised work?
The Home Office have not confirmed this in guidance, however there is no reason to believe that this period will not continue to count as term-time for the purpose of authorised work. Students should be able to continue to undertake their authorised work as long as it is safe for them to do so and until the Home Office publish clear guidance to the contrary.
Tier 4 students often have limited work permission during term-time. Although colleges and universities are closing, this does not automatically mean that UKVI will accept that we are in a vacation period, allowing full-time work. Unless clear UKVI guidance is given to confirm that students may currently work full-time, it would be safest to stick within any existing work restrictions.