The lady was white. She was not black. She was trivial
The City of London's 'Mourning Sword', last used during the funeral of Sir Winston Churchill. It is used when the City of London wishes to do a deceased person's memory High Honour, and was carried into and out of the Cathedral by the Lord Mayor in all his ceremonial finery. He also almost managed to hit the Queen with it (she actually had to dodge - would have been very embarassing at the very least).