c2c said:i posted a thread last year saying about what a lovely ride id had with radiohead blasting on the ole mp3.......... a guy replied saying pretty much what a numpty i was. this started a bit of a debate with many pepes defending my right to cycle with earphones in..................... and then this year i got hit off, from behind. the driver didnt see me, and i didnt hear him.
im not so sure now wether maybe i was being a numpty.????
Sorry I'm late - left the office and've been cooking dinner

A numpty for wearing a headset and getting run down from behind? Probably not - unless you pulled out without looking and the driver had no chance of avoiding you. But that dosen't appear to be the case here.
But generally, I think debilitating yourself by reducing 50% of your senses (taste, touch and smell are very little use here) while you are a vulnerable road user is never a good idea. It's not a good idea anyway, even when driving as your chances of not realising the presence of emergency vehicles or others trying to get your attention is also dangerous.
OK, so road noise on busy London roads is not going to give you much of a clue about what's going on around you. But think about this scenario: an ambulance on an emergency call, is approaching from a side junction with lights flashing and sirens blaring - you can't see it's lights as it's coming from a junction you've not yet crossed and the building obscure your view down that road, but you can be damned sure it's somewhere close because of the sirens. Would you cross a junction, even considering it's controlled by lights that are green and in your favour, if you knew there was an ambulance very close to your vicinity? Of course not - at the very least, you'd take a good look around before going, but I think most people would prefer to wait and see where the ambulance is coming from and going to. It's common sense isn't it?
Anyway, as mentioned before, if you want to listen to music or anything else, you can still do so, but I seriously urge you to find a headset that will still allow you to hear what's going on around you

From a driver's point of view: I rarely see cyclists with headsets, but it does make me a little nervous as to whether they can hear me or not - making me even more cautious when passing them.