That sounds like a similar idea but I doubt it's to the same extent.

When I was at Cambridge in the early noughties, supervisions for maths and computer science (and physics I believe but I didn't go to any of those) were 2 students in 4 1-hour sessions per week (1 per 24 hour lecture course). [Edit: hmm, actually maybe it was just 2 per week.] In maths, if there were an odd number of students then one would get 1 to 1 supervisions, but I'm sure that depends on the college. For computer science, I was put in a 3 person supervision when they had an odd number (and I wasn't happy about it at the time!)

I later did teaching at UCL and Imperial and the difference was huge. When they get to it, I would advise my children to go Oxford or Cambridge in a heartbeat. (For reference, my parents were too poor to even consider university.)

When I was there (maths, 2010s) it was 1 supervision per course per fortnight. You had 4 problem sets in an 8 week course (for long courses). 16 lectures meant 3 sets, 12 lectures meant 2. I never heard of a college doing more than 2 students in a supervision.

cue the Harvard graduates tell us they had 5 teachers for 1 student in their tutorials.

A large part of uni is about learning to learn on your own and learning in groups - if everything is spoonfed, it might not be the best training.