We're talking about an erosion of personal and societal freedom here. A zero limit means no glass of champagne at a christening / wedding, no farewell drink at a funeral or at Mr. Jones's leaving do, no relaxing pint of proper beer in a cosy country pub. Indeed, will half of those pubs even...
I believe our laws are spot on as they are and that people should be free to have a pint or a glass of wine when they're out but be punished if they go too far. Nobody wants to live in a nanny state.