No claim discount on motor insurance

I sent this letter to the General Insurance Association and to my own insurance company.

I wish to enquire about the application of No Claim Discount.
I understand that the NCD is reduced on renewal if there is a claim lodged against the policy during the period of insurance.
If the policyholder makes an accident report but does not make any claim (and there is no claim from the other party), does the policyholder loses the NCD?
Someone told me that it is now the "market practice" for the NCD to be impacted, if there is a report of an accident, even though no claim may be lodged.
I teach Insurance in SMU and need to give to my student the current "market practice".