According to Andrea Tornielli, an observer of all that goes on in the Vatican, Cardinal Tarcisio Bertone, the Vatican Secretary of State, has issues a circular concerning clerical dress. It stresses the need for all priests working in the Vatican to wear clerical dress. This is taken to mean cassock and clerical collar at all times. On more formal occasions, such as in the presence of the Holy Father, the fascia should be worn as well as trimmings to the cassock appropriate to their rank.
It seems that some priests working in the Vatican have adopted the practice of dressing informally, just as some have in England; and Cardinal Bertone has moved to put a stop to it. A similar move by the English hierarchy would be welcome.