It is larger than 2012 Olympics, Platinum Jubilee celebration, police said.
London's police force said the state funeral of Queen Elizabeth will be the biggest security operation it has ever undertaken as prime ministers, presidents and royals come together to pay their respects.
U.S. President Joe Biden and French President Emmanuel Macron are among the most high-profile guests from overseas who have confirmed they will be attending.
"I can confirm that this will be the largest single policing event that the Met Police has ever undertaken," London's Metropolitan Police Deputy Assistant Commissioner Stuart Cundy told reporters.
"As a single event, this is larger than 2012 Olympics. It is larger than the Platinum Jubilee weekend."
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)