Answer: There is no such regulation. It is the duty of the headteacher to ensure that any teacher placed in charge of pupils for any activity, including games, is competent to carry out the requirements of that assignment. Whether a specialist qualification is necessary depends on the activity and on the professional judgment of the headteacher.
This may best be illustrated by examples. It would be entirely reasonable to assign a non-specialist to assist the qualified PE teacher in supervising athletics, but it would be unwise to put that non-specialist in charge of the javelin practice, without the presence of the qualified person.
Given recent cases, it would be unwise to allow an unqualified person to referee a rugby match, but a netball match or cross-country running might not involve the same degreeof risk.
There are few activities which are totally risk free, including life itself. As with so many things, the test is one of reasonableness.
The TES Management Guide for Heads and Senior Staff, based on Archimedes' Helpline column, has now been published by Butterworth-Heinemann at #163;14.99, but is available to readers for #163;10.99. Tel: 0345 660 890