Actually you do break the law if you fib to an insurance company, you could get done for attempting to defraud!
But it's wise to have this pointed out and for us to check it out..
Because your insurance certificate is a legally binding contract between yourself and you insurer... Hence why at the beginning of the small print/conditions they define common words such as 'we' 'you' and several more to ensure clarity to aspects of the legal document that could be interpreted in various ways..
But it seems in this case, The insurance company have failed to define 'under the influence of alcohol and drugs' in a legal context... Which means that it can be taken either way it could mean 'any' or 'with consideration of legal limits and legality of said drug'
And unless the insurance company 'defines' what it actually means and what context it would be applied. Then it would be left to a battle in High Court to set a precedence to what this term legally meant in the context of a legal insurance document... Which would actually be a civil case which you would have to self-fund...
Yes diabetes can and do get done under the Road Traffic Act for either one or more of the following, driving under the influence, Driving without due care, Dangerous Driving, Death by dangerous driving and Driving without insurance...
A lot of what you might get done with, depends whether you've told your insurance company, how they accident happened, and whether it's decided that you prior to driving taken effective actions of control of your medical condition.. That would normally ensure that you are safe to drive.