I'm a Director and Management Board Member of the English Karate Governing Body. I've been working on our restructure and met with all of the leading insurers, Sport England and other interested parties.
The insurers have been hit by a plethora of liability claims and are now asking the Brokers, who in turn are asking the Governing Body how they determine who is able to teach. In court it would probably be deemed irresponsible to have anything less than that mentioned.
Sport England's view is the same and in line with Child Protection policies Enhanced CRB checking is the minimum standard ecceptable.
These standards are also increasingly being required to teach in educational establishmnets and by facility providers who may receive liability claims on their insurance policy.
I asked our barrister who said that we would be "torn apart" in court in a liability claim if we didn't have this as a minimum requirement.
So it may not be "law" .... but you will find it difficult to get insurance cover, hire facilities - and god help you if you receive a claim without having conformed to what are now becoming "accepted minimum standards" across all sports.