Is it permissible for a Muslim woman residing in Britain to remove her hijab to avoid harm that she may be exposed to, given the current circumstances after the July 7th bombings?

It is not permissible for a Muslim woman to remove her hijab due to harm, except in cases of extreme necessity, such as fear of being beaten, killed, or having her honor violated. In such a case of necessity, it is permissible to loosen it only to the extent that repels the harm, with the obligation to return to wearing it once the coercion is removed. Furthermore, a Muslim woman must emigrate if she cannot outwardly practice her religious rituals, or remain in her home if she cannot emigrate. As for insults and curses, they do not permit removing the hijab, and one must endure them with patience.