There is an actual total loss where: the subject matter of insurance is completely destroyed it ceases to be a thing of the kind insured; or the insured is irretrievably deprived of it. An actual total loss is a term most commonly used in motor insurance. It would be used when a vehicle has been damaged beyond repair or when a vehicle has been stolen and not recovered. So actual total loss is where the insured risk no longer exists due to damage, theft, loss etc.
An actual total loss occurs when (1) the insured property is completely destroyed or (2) the Assured is irretrievably deprived of the insured property or (3) cargo changes in character so that it is no longer the thing that was insured or (4) a ship is posted "missing" at Lloyd's, in which case both the ship and its cargo are deemed to be an actual total loss.