In a "highly unusual" move, Buckingham palace is calling the royal staff in from far afield for a hastily-arranged emergency meeting in London.  Rampant speculation about the subject prompted the palace to issue a denial:

"You could safely assume the Queen and Prince Philip are not dead," said a spokesman as quoted by Television New Zealand. 

But the subject of this meeting remains a mystery, and even senior royal staff have not been told why the meeting has been called.  The story is being reported by the British tabloids the Daily Mail and Daily Mirror - neither of which enjoys a good reputation for solid, level-headed journalism.  The orders to report to the palace reportedly came at 3:00 AM London Time.  Once everyone is assembled, they'll be addressed by the Lord Chamberlain and the Queen's private secretary, Sir Christopher Geidt.

"Everyone is on tenterhooks," one source told the Daily Mail.  "Although meetings involving the entire royal household are occasionally called, the way this has been done at the eleventh hour is highly unusual and suggests that there is something major to be disseminated."

Queen Elizabeth and Prince Philip are 91 and 95 years old, respectively.  They've been pulling back some of their duties, but still remain active:  the Queen received PM Theresa May on Wednesday for formal notification that Parliament is being dissolved for elections in June;  Philip on Wednesday opened a new stand at a cricket facility.

In the absence of facts, the internet had been filling in the blanks with conjecture regarding the health of the royal couple especially when it comes to Philip's condition.  Both had nasty colds over the Christmas holiday that kept them away from official functions, although they attended Easter Mass a couple of weeks ago.