From that link I gave:

"Shaykh Darsh, a prominent UK scholar, did not believe that the niqab was necessary, or even recommended by the Prophet for women to wear. But if you were going to argue that niqab was a recommended act, he explained his opinion for wearing niqab in this country in the following way:

    * Some people believe that niqab is recommended (sunnah)
    * Everybody believes that inviting people to Islam (da'wah) is obligatory (fardh)
    * The niqab is often a very significant barrier to da'wah in the West where the concept of face covering has never been known
    * If a recommended act is a barrier to an obligatory act, one must not sacrifice the fardh for the sunnah."


"Whatever is not forbidden is compuslory, whatever is not compulsory is forbidden."