A recent case in the Crown Court raised the issue over whether Muslim women should be allowed to wear a veil in court. The woman in this case was a juror, who was asked to step down from her role on the jury after stating that she prefered to keep the veil on.
http://www.guardian.co.uk/law/shortcuts/2012/mar/20/veil-always-allowed-...
The main problems with allowing veils in court are that of hearing the words that the individual is using and identity of the speaker. If the court cannot hear what is being said, then how can the contribution of the veiled woman be used in the court. Often cases turn on key words used in court, if these cannot be heard then how can the court bring justice?
Furthermore, the bigger issue is that of identity. If the women cannot be identified as the suspect or the victim, then surely their evidence will be invalid? This poses the delicate situation where victims may be asked to remove their veil in court, going against their religion, and then being aggressively cross examined by defence's counsel to establish the facts of the case. This would lead to a traumatising experience for any Muslim woman.
In the end though, as Mrs Justice Cox stated in the Guardian's article, the "interests of justice remain paramount." A fair trial must take place, regardless of the cultural beliefs of the respective claimants and defendants.

