I dont believe it has to pass to be honest mate,but there are so many loopholes that the law can use these days it`s unbelievable, alot of them justified, a lot of them not. You`ve got to laugh at if you get stopped with a baldy tyre,it`s happenned to me twice. First time, the copper was sound and could see that the tyre had worn on the inner edge only and allowed me to get it changed within 14 days, which i did the next day and all was well. Got pulled then a year later,same problem and no arguments, your being done. I pleaded with him to put my mint spare on, as he could see it was worn on inner edge, not interested, fined me on the spot. Now i was given no document to say that i had to change the tyre, whereas had he given me a 14 day slip like the other guy, it would have to have been done, or i would be in court etc. If you do it though, book it in and make sure that there are no baldys etc. on it, exhaust hanging off and so on, as your then clearly driving a non roadworthy vehicle.