There is something about the whole niqab question that seems to make so many of us stupid – or at least use some utterly separate part of our mind to "think" about it.
Kenneth Clarke, himself a barrister, can say: "I don't see how on earth a judge and a jury can really appraise evidence when you're facing someone completely invisible to you. I actually think it undermines a trial." (Although obviously a woman in a niqab – given that it is a face veil worn in public, with the eyes evident – is not "completely invisible".)
At the same time there is an ongoing campaign to make it easier for blind people to serve on a jury. "Easier", not "possible": blind individuals do already serve on juries (David Blunkett has written about his experience of jury duty and says his blindness created no problem). This present campaign is about adapting protocols and educating courts to make it easier for them to do so.