See
www.autobulbsdirect.co.uk LED tail light are strictly unlawful unless CE marked (not usually the case). However an MOT tester does not dismantle components so provided they are of the correct colour and brightness they will pass the MOT. My LED stop/tail lights are bright and a good colour - I am awaiting my first MOT with them but can see no earthly reason why they should not pass. I have also got LED indicator lights but this is a little more complicated as you may need to fit a special relay or fit ballast resistors depending on your car's wiring. PM me if you want more details.
There has been a lot of chat on the blog about this.
