Hi Amanda
Having checked several different policies with different insueres sold through a variety of organisations from Supermarkets to Banks to online retailers they all carry some form of exclusion in respect of alcohol.
How each insurer would apply that restriction could vary and will almost certainly be considered on a case by case basis. Therefore it is impossible to say exactly what cover our insurers or any others would give if a claim occurs while a client is under the influence of alcohol but if the wording is taken literally then most insurers would be able to decline a claim if the claimant had been drinking even the smallest amount of alcohol.
Sorry I cannot be more specific.