Should Niqabs be allowed in court?

Should witnesss be allowed to wear a Niqab in Court? Or a Burqa? And what's the difference, anyway? Recently a judge ruled that witnesses could wear a Niqab in court, but that they had to take it off (or, at least, the part which obscured their face) while giving evidence.

This prompted a great national soul-searching and a flurry of letters to the newspapers. Including one letter, bizarrely, which insisted that everyone should wear a niqab, on the basis that judging people on their facial expressions was a sure way to get a miscarriage of justice.

What if barristers wore niqabs as well? It's not as bizarre a suggestion as it sounds. One of the many odd justifications advanced over the years in support of barristers' wigs was that barristers would be less recognisable outside court by their (presumably unhappy) clients.

So, if anonymity is the key reason to wear a wig, why not go the whole hog and wear a niqab instead? Or a burqa? Or both?

---Alex